Yes, the output is uglier. But, this is necessary for me to refactor
`replaceSupers` for #7733, which is necessary for both #7555 and
https://github.com/babel/babel/pull/7553#issuecomment-381434519.
I'm still in the middle of cleaning up all this code. Don't expect
`transformClass` to survive much longer as it's written currently.
We were using `Object.create` to setup the prototype chain at the start of the class definition, which lead to #7771.
I was a bit worried about a speed hit, but it seems everyone optimizes the two patterns the same way.
https://jsbench.github.io/#f9fca52407643d96458a35763b201215Fixes#7771.
* Implement MemberExpressionToFunctions helper
Fixes#7733.
This will also be used to simplify the Private Fields transform, which had [almost the same code](ccd941057a/packages/babel-plugin-proposal-class-properties/src/index.js (L114-L217)) hand written.
* Cleanup
* Little more comment cleanup
* Use unary plus
This can't be redefined, unlike the `Number` identifier.
* Review comments
* Remove unused deps
* drop support for Node.js v4; closes#7753
- remove version 4 from Travis build matrix
- update environment support doc
- update `CONTRIBUTING.md`
- update `engines` field of root `package.json`
Signed-off-by: Christopher Hiller <boneskull@boneskull.com>
* update engines for babylon
Signed-off-by: Christopher Hiller <boneskull@boneskull.com>
* Improve asyncIterator error
When an object is has neither asyncIterator or iterator defined, throw the "not an async iterable" error
* Correct logic
* reduce access
* Update helpers.js
* Update decorators parsing
This commit introduces three changes:
1) Class properties can be decorated
2) Decorators can contain arbitrary expressions, using @(...)
3) The Decorator node type has a new property, "arguments". This
makes it possible do distinguish @dec() and @(dec()), which have
different behaviors because @(dec()) is equivalent to @(dec())().
* Rename Decorator#expression to Decorator#callee
* Add test for @dec()()
* Fix class properties after nested class' bare super
Fixes#7371.
* Fix node 4 test
* This damn node 4 test
* All of the ClassBody, but not the methods or field inits
* tmp
* tmp
* Use common class environment visitor
* Tests
* Use skipKey to avoid recursive traversal
* Remove old state
* Use jest expect
* Properly traverse nested class for supers
* Add object nested in class cases
* Add object nested object cases
* Test class properties
* Undo changes to lerna.json
* Add tests arournd prefix/postfix super increment
* tmp
* Use sets
* Improve get/set helper
* fixtures
* Edge cases
* Add loose edge cases
* Spec compliant
* Add issue case
* Even more edge cases!
* Final updates
* Fix name
* Use Reflect.{get, set} when available
* Avoid block scoping in loose
* Remove semicolon
* Do not redefine a non-enumerable
* Get strictness from call site, not helpers
* Add called assertions
* Classes are always strict
* Update test fixture
* #7349
- Add "use strict" directive to transformed class bodies
* Update tests (#7349)
* Add test for program with use strict directive (#7349)
* Update tests (#7349)
* Update source mapping (#7349)
* Add test for parent blockStatement with use strict directive (#7349)
* Update tests (#7349)
* Update tests (#7349)
* Update tests (#7349)
* Add test for constructor-only class (#7349)
* Constructor only classes are strict, too
But constructor only that use non-simple parameters must use a strict function wrapper.
* Fix test
* Wrapper not needed if class is already strict
* Revert change to lerna.json
Added the value argument to the visitors of flow literal type
annotations.
Literal type annotations need a value since they work very much like
primitive literals in normal JavaScript.
Fixes#7697
* Fix name computation for literal values
* Add more computed literal test cases
* Always return a string in getNameFromLiteralId
- Also concatenate quasis id for regex literal
* Add a test clarifying function name for template literals
* Remove useless else ifs
It was needed to avoid collision of identifiers used in fields
initializers with variables declared in the constructor, but it
broke `this` handling.
This commit removes that behavior and instead renames the
colliding variables.
* Add support for RegExp includes/excludes
* Keep the plugin order
* Detect invalid modules in regexp
* Add more tests for regexp
* Cover builtins, and unnormalized in the RegExp tests
* Remove babel-plugin- in all positions
* Change babel-plugin- prefix to string
* Add a test for the same module in include/exclude
* Handle partial matches explicitly
* Remove extra valid regexp check
* Optimise validation of plugins
* Optimise selecting the plugins
* Fix undefined include/exclude option
* Update documentation to reflect the new include matching
* Fix typo
* Apply reviews
Use regexp.test instead of string.match (slower)
Define flatten helper
Do not normalize babel-plugin anywhere in the string
These files appear to have been missed in the update of test file naming from actual/expected.js to input/output.js. As a result, they were silently not being run. I've confirmed that they were not running, updated the names, then confirmed that they are running now.
The boolean expressions returns false in environments where Map is missing.
This change explicitly sets _cache to undefined in such cases, to ensure the cache methods will be ignored.
* docs(babel-standalone): remove bower mention
Since the package won't be downloadable as `@babel/standalone` it's best to just remove it, since it's pretty much deprecated as is. I left the other mention of babel-standalone-bower since I guess that's just the name and still useful in other cases
cc @daniel15
reported in https://github.com/babel/babel/pull/6495#pullrequestreview-70980926
* Update README.md
* Update test262 and whitelist
* Use test262-stream
* Check escapes in contextual keywords
* Check escapes when parsing new.target
* Check escapes for getters/setters
* Check escapes for static class methods
* Check escapes on async arrow and functions
* .prettierrc: full configuration for Prettier
This way, contributors using different-from-default settings will still
use the correct prettier settings
* Makefile: also lint .babelrc.js
* Makefile: also prettify .json files
* Exclude package.json files and correct build dir
* Add more default options to prettierrc and load it in cli
This avoids prettier looking up the config for each file
* Format json
* Update prettier and eslint and reformat codebase
* Remove obsolete file
* Add comment
* Fix reseting modules in jest and config
we have lib folders inside the source folders which should not be ignored.
* Add codemods lib folder
* Support mjs
* improve ignore pattern
for-await was transformed in @babel/helper-remap-async-to-generator, which was
called by @babel/plugin-transform-async-to-generator and
@babel/plugin-proposal-async-generator-functions. This prevented for-await
statements in async functions to be transpiled if the
transform-async-to-generator plugin was't enabled.
* feat(babel-cli): add a brief summary to build output
* address feedback
* further adjustments
* Use quiet output as default, add --verbose
* fix tests
* remove verbose alias
Prior to this change, we'd conduct an open-ended traversal on the 'id'
of any VariableDeclarator to find a RestElement. The 'id' of
a VariableDeclarator can contain an AssignmentPattern (to supply
a default value), and if the right-hand side of the AssignmentPattern
contained a RestElement, we'd transform it.
The problem here is that the right-hand side of an AssignmentPattern can
be *any* Expression. If the right-hand side is a function body, we'd
traverse the entire function body, and if a RestElement occurred
anywhere in that function body, we'd transform it and emit the
transformations wherever we began the traversal (at least one scope
outside its usage).
The fix is to stop the inner traversal if we encounter an
AssignmentPattern. The outer traversal will still visit the
AssignmentPattern, so RestElements within the right-hand side of an
AssignmentPattern will be properly transformed at that time.
This creates a new package called @babel/highlight which syntax highlights
JavaScript code for terminal output. This functionality was already
present in @babel/code-frame, but exposing it as a separate package lets
other projects leverage it. @babel/code-frame has been refactored
slightly so that it uses @babel/highlight to do its syntax highlighting.
* Added optionalExpression types to babylon and babel-types
* OptionalChain transforms bug fix
* Added OptionalExpressions to babel-generator. Fixed OptionalChain Bugs
* Removed 'optionalChain' from newExpression and added test cases
* Added test cases for optionalChain
* Update index.js
This failing test case demonstrates a regression between 7.0.0-beta.38 and
7.0.0-beta.39 in the @babel/plugin-proposal-object-rest-spread package.
I distilled this test case from a larger configuration of plugins in my
application, one of which calls api.traverse.cache.clearScope(). Although
calling clearScope() is an uncommon thing for a plugin to do, it was a
reliable way to reproduce the problem. If I can find other reliable
reproductions, I'll push some additional failing tests to this PR.
Regardless of how common it is, clearing the scope cache should be a safe
operation that only slows down the transform (because scopes have to be
recreated and re-crawled). Crashing due to a spurious duplicate
declaration seems like a bug worth fixing.
My hunch is that [these two lines](eb38ea2b10/packages/babel-plugin-proposal-object-rest-spread/src/index.js (L75-L76))
(which were changed in `7.0.0-beta.39`) are not actually removing the
original rest element as a binding from the enclosing `Scope`, in certain
circumstances, so the new variable declaration ends up colliding with the
old (removed) binding.
Possibly related: #7304 (reported by @julien-f)
* generate typescript types
* improve type generator output
* move generator scripts to scripts/generators
* use new stringifier for generating flow types too
* export summary types
* add support for oneOfNodeOrValueTypes to improve type generation
* export typescript types from top level, and remove module declaration
* generate typescript/flow types and copy typescript types to babel-types/lib as part of make build
* copy flow types to babel-types/lib as part of make build (fix#6839)
* improve typing: Identifier->name should be a string, not any
* avoid destructuring, to support node 4
* update doc generator to share more code, regenerate babel-types readme, pipe all generator output to stdout
* regenerate babel-types readme as part of make build
* improve typing: ClassProperty->key should be Identifier | StringLiteral | NumericLiteral | Expression, not any
* improve typing: optional node properties are nullable, not undefinedable
* improve docs: FlowClassImplements should be ClassImplements
* make ts usage more friendly: when using babel-types api, make optional params | undefined, and when reading nodes keep optional params | null
* rm lib/types.d.ts and lib/types.js in favor of packages/babel-types/lib
* add missing variance node type, address review comments
* add tests for flow variance
* Comment should be a disjoint union of tagged types
* update .flowconfig
Keeping the shape of an object constant is a performance improvement for modern javascript engines. At the point of the code change it is certain that the `children` property will be set later, so the property can already be set to `undefined`.
* use the async version of transform in babel-cli
* Modify compile to use async version of transformFile
* Babel-CLI: transform files sequentially
* Remove useless res in callback
* Add test case for simple reference in tdz
* Add more examples from old issues as test cases
* Fix two testcases by excluding function declarations from being tdz checked
* Document the option for block-scoping
* Add test cases with destructuring assignments
* Remove failing test cases
* [skip ci] Include type and default value for options
* Bail out on JSX fragments instead of throwing
The `transform-react-inline-elements` plugin doesn't handle JSX fragments. It throws an exception because `node.openingElement` is undefined.
* Add a comment explaining `node.openingElement`
* Update line endings in test fixtures to match current output
* Fix incorrectly set up static-property-tdz fixtures
It seems the fixture runner does not look into subfolders.
* Remove expected file that should not exist
* Reenable disable optimisation test
* Reenable disabled nbsp tests
* Reenable comments between props test
The comments adjacent to children test is still broken so it stays off.
* Avoid adding #__PURE__ annotation to .bind(this)() expressions
Fixes the #__PURE__ annotation getting added to (async () => {})() IIFEs when the arrow function transform is running with spec: true.
* Return false instead of undefined
* Fix indentation in json files
* Add one more case to the async-iife fixtures
* Better error messages when Babel fails to parse import = and export = syntax from typescript when using babel-plugin-transform-typescript
* Fixing Test cases
* Ran make fix and broken looong sentence into smaller
* Slight changes to Messages after review with Nicolo & existentialism
* Removed trailing space
* Handling babylon parsing errors in a better way
* Better error messages + Helpful URLs
* Replaced message from babylon completely
* Add importMeta plugin to the map
Currently, Babel is treating JSXIdentifier, JSXMemberExpression, and JSXEmptyExpression as expressions as well, which means Babel will for example incorrectly allow you to place these anywhere an expression is wanted.
Closes#6851.
`this.blockPath.get("body")` constructs an array of paths corresponding to each node in `blocks.body` so takes O(n) time if n is that length. We were re-constructing that array on each iteration, so the entire loop was O(n^2).
On files with many statements in a single block (such as Rollup-generated bundles), this takes a large portion of time. In particular, this makes transforming react-dom.development.js about 40% faster. Not that you should be transforming our bundle with Babel.
Test Plan:
Make an HTML file with these three lines and watch it in the Chrome Performance tab to see timings (on my machine: 2.9s before, 1.6s after):
```
<!DOCTYPE html>
<script src="https://unpkg.com/babel-standalone@7.0.0-beta.3/babel.js"></script>
<script type="text/babel" src="https://unpkg.com/react-dom@16.2.0/umd/react-dom.development.js"></script>
```
This commit introduces 4 changes:
1) Function declarations are wrapped using function declarations.
This has two advantages:
- We can rely on native hoisting, instead of using _blockHoist
- The function isn't wrapped until it is called. This avoids
problems where `regeneratorRuntime.wrap` was called before
that `babel-polyfill` was imported.
Example:
function fn() {}
// becomes
function fn() { return _fn.apply(this, arguments); }
function _fn() {
_fn = _wrapper(/* Original function ... */);
return _fn.apply(this, arguments);
}
2) Use a single template for both named and anonymous function
expressions. They already had the same behavior, but the one
used for named functions was a bit longer.
3) Use normal functions instead of arrow functions to wrap
function expressions.
4) Generate a name based on the original one for wrapped
functions (e.g. `foo` becomes `_foo` instead of `_ref`).
* Split exportExtensions into two plugins in babylon
* rename proposal-export-default to proposal-export-default-from
* rename proposal-export-namespace to proposal-export-namespace-from
* Consider reexports for bindingKindLookup.
* Update test cases according to reexports change
* Fix order for assign reexports.
* void 0 assignation to module keys only for loose mode.
* Create buildReexportsFromMeta helper.
* Update umd/amd fixtures.
* Refactor reexports build.
* Hoist template for reexports.
* Use map as a second argument of Array.from.
* Remove unnecessary export.
* First implementation sketch and testcase
* Use helper instead of inline IIFE's
* minNodeVersion 6.0.0
* Hoisted visitor for subtraversal and fixed edgest case
* Resolve merge conflicts in helpers
* Remove duplicated helper from messing up Git
Flow bindings have been deprecated for a while.
The reason behind this change is that `declare var foo`
doesn't introduce a new local binding, but it represents
a global one.
* Install sourceMapSupport only when sourceMaps are requested
* Add tests for sourceMapSupport
* Fix sourceMap position for tests
* Fix gen_error file
* fix the test descriptions
* Refactor install sourceMap support
* Run sourceMapSupport only once
* Handle cases where sourceMaps is undefined
* No unneeded empty arrays in transform spread
Since Array.prototype.concat creates a new array from inputs, there's
no need to call it from a new empty array ([].concat()).
* [fixup] simplify detection of new array
* Fix transform-arrow-functions in { spec: true } shadowing
The function name matching the variable declaration name could
shadow the actual function object inside the generated function,
leading to invalid behavior due to holding a reference to the
original unbound function.
* Combine it with transform-function-name just to be sure in spec: false
* Revert "Fix transform-arrow-functions in { spec: true } shadowing"
This reverts commit 1cafe2561d0b0ddd181b956a85eb074621da12e8.
* Much simpler version of the above fix
* Missing fixture updates
* Avoid using rest/spread to make the tests pass on node 4
* ...actually update _all_ the fixtures
* Unify eslint/prettier config
Use a prettier config file and correctly configure trailing commas
Enable curly in babylon as in all other packages.
* Add experimental and codemods
* Properly guard for..in loops with Object#hasOwnProperty.
I noticed that babylon spends a lot of time in what we call *slow mode*
`for..in` when running in Node (on V8), and the reason for that is that
the version distributed on npm is build with *loose mode*, which turns
methods on the prototype into enumerable properties. Let's look at a
simplified example of the `State` class from `src/tokenizer/state.js`:
```js
class State {
constructor() { this.x = 1; }
clone() {
var state = new State();
for (var key in this) {
var val = this[key];
state[key] = val;
}
return state;
}
}
```
According to the specification the `State.prototype.clone` method is
non-enumerable. However when transpiling this with loose mode, we get
the following output:
```js
var State = (function() {
function State() { this.x = 1; }
State.prototype.clone = function clone() {
var state = new State();
for (var key in this) {
var val = this[key];
state[key] = val;
}
return state;
}
return State;
})();
```
So all of a sudden the `State.prototype.clone` method is enumerable.
This means that the `for..in` loop inside of that method enumerates
`x` and `clone` for `key`, whereas originally it was supposed to only
enumerate `x`. This in turn means that the shape of the result of a
call to `clone` will be different than the shape of a state that is
created via the `State` constructor. You can check this in `d8` using
the `--allow-natives-syntax` flag and this simple test driver:
```js
const s = new State;
%DebugPrint(s);
%DebugPrint(s.clone());
```
Using either the class version or the transpiled version we see:
```
$ out/Release/d8 --allow-natives-syntax state-original.js
0x2a9d7970d329 <State map = 0x2a9d40b0c751>
0x2a9d7970d3c1 <State map = 0x2a9d40b0c751>
$ out/Release/d8 --allow-natives-syntax state-loose.js
0x3729ee30d1b9 <State map = 0x3729af90c701>
0x3729ee30d251 <State map = 0x3729af90c7a1>
```
So as you can see, the transpiled version (using *loose mode*) produces
a different shape for the result of `clone`, whereas the original
version is fine. This pollutes all sites which use either a state
created from the `State` constructor or returned from the `clone`
method. The original one has only the `x` property in either case,
whereas in the transpiled version the result of `clone` has properties
`x` and `clone` on the instance.
To mitigate this effect, it's best to guard the `for..in` loops with
`Object.prototype.hasOwnProperty` calls, such that the actual body of
the loop only deals with own properties and not with properties from the
prototype chain. This change does exactly that for the two affected
`clone` functions.
In addition to the performance hit because of the unnecessary
polymorphism, there's also the performance hit because of the *slow
mode* `for..in` itself, which has to collect the properties from the
instance plus the prototype. Ideally the prototype properties shouldn't
be enumerable to avoid this whole set of problems. I see a couple of
possible solutions:
1. Distribute the original ES2015 version via npm.
2. Don't use loose mode, so that `Object.defineProperty` is used
instead, correctly passing `enumerable:false`.
3. Globally change loose mode in Babel to generate the correct and
fast `Object.defineProperty` instead.
I'd personally prefer a combination of 1. and 3. here, but I'm aware
that distributing the ES2015 code might not be an option yet. So the
mitigation of properly guarding the `for..in` here should already help.
But it'd be nice to have a discussion on using `Object.defineProperty`
in general, as I imagine that this could easily bite other applications
as well and this performance cliff is completely unobvious to
developers.
* Switch to Object.keys and Array.prototype.forEach.
- This is because with scoped packages the `latest` package was the first publish we did
- This happens to be beta.4..
- So in this case we should publish whatever version as latest anyway
* Consider instance type for polyfills.
* Add test cases for evaluated objects.
* preset-env fixtures: babel-polyfill -> @babel/polyfill
* Split up fixtures with evaluated variables.
* Add JSX Fragments to babel-types
* Support JSX fragments in the transform-react-jsx plugin
* Add tests JSX fragments
* Update helper-builder and transform plugin documentations for jsx fragment
* Add generator for jsx fragments
* Add test for jsx fragment generator
* Split jsx transform example into normal and fragment examples
* Remove unnecessary fields from ElementState in babel-helper-builder-react-jsx
* inline [skip ci]
* Use parseFunctionParams to parse method parameters
* [funct] Set this.state.inGenerator before parsing the function name/params
This allows "yield" inside generator parameters to be actually
parsed as a yield expression
* [funct] Disallow yield in function parameters
* [arrow] "yield" can start an arrow function (e.g. "yield => {}")
* [arrow] Disallow YieldExpressions inside arrow parameters.
* [err msg] Disallow yield as fn name in strict mode using checkReservedWord.
So Babylon throws "yield is a reserved word" instead of
a custom "Binding yield in strict mode"
* [err msg] "X is reserved in strict mode" should have precedence over "X is reserved", since it is more specific.
This was observable if "checkKeywords" is true and the word is both a keyword and a reserved
word in strict mode
* Disallow "yield" as an identifier inside generators
* [tests] Add tests, update wrong esprima tests and enable disabled esprima tests
* [tests] Move uncategorized tests to es2015/yield
* [tests] Update test262 whitelist
* Fix regression introduced by 8c77073
* [tests] Update flow whitelist
* Fix flow errors
- adds `get` and `set` kind in addition to `method` to the list of allowed class members for having a decorator,
- adds tests for this two cases (decorator + set and decorator + get)
Similar to the fixes in https://github.com/babel/babel/pull/6580 and
https://github.com/babel/babel/pull/6581, accesses of the form
```js
stack[stack.length - 1];
```
when `stack` can be an empty array are pretty bad for performance.
In this case it also breaks the type safety, since the function
`last<T>` is declared to only return values of type `T`, but
occasionally also returns `undefined` now, since the `stack` parameters
passed to it never contain a property `"-1"` and neither do the
`Object.prototype` or the `Array.prototype`.
This is a non-breaking performance fix, which adds proper checking
to ensure that `last` is only invoked on non-empty arrays.
Amusingly the pipeline OP "breaks" the readme formatting because Markdown likes the `|` character a bit too much. Escaping the `|` fixes this and makes the readme display properly
* Re-name uncatagorised 1 and 2
* Move to es2015
* Add expected.json to parenthesized lhs object
* Orginize into parenthesized-lhs-array and parenthesized-lhs-object
* Remove uncategorised/33 because it was repeditive decorators/class-decorator
* Move uncatagorised/34 to decorators/class-decorator-assignment
* Move uncategorised/35 to decorators/method-decorator
* Move uncategorised/36 to decorators/class-decorator-setter
* Move uncategorised/37 to decorators/class-decorator-getter
* Move uncategorised/38 to decorators/class-decorators-multiple
* Clean up syntax
* Move uncategorised/39 to decorators/object-decorator
* Remove syntax in order to pass tests
* Re-add uncategorisd/33 as decorators/class-decorator-new-line
* Move class-decorator-new-line to class-decorator-same-line
This separates `classPrivateMethods`'s dependency on
`classPrivateProperties`. It also starts a `PrivateName` at the hash
symbol, not the `Identifier`.
* Add support for class private methods
This commit adds parser support for the TC39 Stage 2 Private Methods
proposal.
This commit also changes "key" in ClassPrivateProperty from an
Identifier to a PrivateName, as well as disallowing #constructor as a
valid private field name.
* Add tests for string literal get/set/async
These should be treated as regular methods and not special get/set/async
behaviour.
* Add tests for class private methods
This also removes a test from the Test262 whitelist that failed before
the changes for private methods support and now passes.
* Modify class private prop tests for PrivateName
* Add class private prop tests for #constructor
* Fix existing ASI test case failure
Given that it refers to an identifier, it's somewhat confusing to have
to use .name.name to get the actual string. The type declared within
types.js is also incorrect, which this commit fixes.
This change has two reasons:
- The object was actually used as a map
- Using an object leads some problems with the
private_class_fields/constructor.js test, since
`tests[test_name] || {}` returned the Obejct
constructor instead of an empty object.
* Integrate Test262
Introduce a GNU Make target for retrieving TC-39's Test262 suite and
validating parsing of the files it contains. Interpret each file as a
parser test in accordance with that project's `INTERPRETING.md`
document. Allow for the specification of allowed failures via a
"whitelist" file so that the test suite may help prevent regressions in
this project in situations where this project has known bugs. Initialize
the "whitelist" file with a listing of all tests that are currently
failing. Extend the continuous integration environment's configuration
to automatically run these tests.
* use graceful-fs and latest yarn on travis
* Arrow fns can't be used as the left side of a binary or ternary expression
Fixes#536
* Add test for logical expression with arrow function
* Fix eslint
* Add optionality to catch bindings (plus tests)
* Update ast/spec, README, set param to null if no param with plugin optionalCatchBinding
* Fix: wrap param = null in else case
* Fix tests for optional catch binding; add tests which include finally clause
* Distinguish between ternary's : and arrow fn's return type
* Correctly parse nested arrow functions inside conditional expressions
Defer the conversion of arrow function parameters to assignable nodes so that
it is possible to use the (invalid) ast to get the exact position of the (wrong)
arrow functions.
* Check params of arrow fns w/ type params or w/o return type
* Fix also async functions
* Add test from prettier
https://github.com/prettier/prettier/issues/2194
* Don't check arrow params if they are valid at the first attemp
* Use state instead of relying on the "noArrowParamsConversion" parameter
* Remove noArrowParamsConversion
The parsing of private fields checks whether or not it is within a
class to determine if it is valid or not. However, the state.inClass
property is incorrect as it marks it as outside a class when the inner
class is closed.
This commit fixes this problem by replacing the state.inClass property
with a class nesting counter.
Given that private fields can only be used within classes, any code
using them must be in a strict mode context. As private fields cannot
be deleted, throw an early SyntaxError.
* Add plugin for import.meta proposal
Fixes https://github.com/babel/babylon/issues/539
* Tests for assignment/mutation of import.meta
* Use correct identifier in failure message
* Simpler & more consistent script errors for import.meta
* Add support for declare export
* Do not allow declare module inside declare module
* Reallow module exports outside module
* Add handling of `declare export default`
Add check for multiple module.export declarations
* Disallow export let/const/type
Refactor parsing object properties to share more code and add support
for getters and setters
* Rename tests
* Update test fixtures
* Optimize for performance
* disallow declare export interface outside of module
* Refactor code to be more readable and less lookahead
* Add comments
* Add test for export star as
* Test for number literal getter/setter
* Add more tests
* Fix tests
* Allow union types and correctly eat semi after type
* Use non computed keys
* Fix tests
* Add support for flow type spread (#418)
* Add support for flow type spread
* Broaden spreadable types from primary to all, more tests
* Eliminate variance sigil for type spreads, better errors, fix tests
# Conflicts:
# src/plugins/flow.js
* Fix tests
* Add support for flow type spread
* Broaden spreadable types from primary to all, more tests
* Eliminate variance sigil for type spreads, better errors, fix tests
* Test runner: Detect extra property in 'actual' but not in 'expected'.
Also update all expected.json where this would result in errors.
* Include rmExpected.js script in case it is needed again
* master:
Upgrade flow to 0.41
Throw error if new.target is used outside of a function (#402)
Fix watch command (#403)
Update yarn lock
Fix parsing of class properties (#351)
# Conflicts:
# src/parser/statement.js
# test/fixtures/experimental/class-constructor-call/illegal-key/options.json
* Fix negative number literal typeannotations
Also use parseLiteral() to parser string and number literal typeannotations
so that future changes (estree) to literals are also reflected to flow.
* Instead of invalid fallthrough throw immediately
* Increase coverage and better error mesage
* Initial estree support for ClassMethod
* Handle literals for estree
* Fix regex
* correct output of regexp and regenerate test
* Add tests for validation stuff with estree plugin
* Parse Properties correctly
This also refactors how babylon parses obj properties in general
so that this logic can be more easily extended.
* Run all throws-tests a second time with estree plugin
* Fix all throw tests
* Remove rebase conflict
* Correctly set kind
This ensures state.inMethod gets propagated correctly
* Add computed: false to methods with ident async
* Implement directive field on Directives
* Test invalid directives
* more tests
* [Flow] Function predicate declaration
The accepted syntax for function declarations is extended to allow
the following predicate declaration:
FunctionReturnType :=
Type
Predicate
Type Predicate
Predicate :=
%checks
%checks ( ConditionalExpression )
* [Flow] Minor tweaks and more examples to function predicates
* [Flow] Clean-up and better message for function predicates
* [Flow] Adding abstract function predicate example
* [Flow] Rearranging the `predicate` field to ease babel generator.
* refactor(tokenizer): use class for keywork tokens
* refactor(tokenizer): re-use constacts in types
* refactor(tokenizer): binop token type
* feat(tokenizer): use beforeAndStartExpr for shortcut
* fix(tokenizer): typo in keywordTokenType
* refactor(tokenizer): don't use spread operator
* refactor(tokenizer): constant for isLoop, isAssign, prefix, postfix
* fix(tokenizer): remove constant beforeAndStartExpr
* style(tokenizer): space after comma
Adding the line `this.state = this.state.clone();` in a parser plugin
(specifically, in my case `parseExprAtom`)
would break decorators.
This change fixes that.
* Use fromCodePoint to convert high value unicode entities
* Include polyfill for String.fromCodePoint
* copy and adapt fromCodePoint into String.fromcodepoint
In order to avoid modifying String as the polyfill does, I've copied
the source from the polyfill and adapted it return the polyfill
function if the native version does not exist. Once support for node
versions that lack fromCodePoint is dropped, this polyfill can be
removed.
* move license notice to top of file
* Run tests of flow with babylon
* Fix travis
* Fix typo
* Again...
* Brtter hint
* proper exit code
* Fix some flase-positives and better reporting
* Enable some plugins, that flow supports by default
* Parse flow nested array type annotations like number[][]
Fixes#217.
* Do not parse a newline separated array statement into a flow type annotation
* Get rid of lineBreak dependency in flow.js in favor of higher level method
* Add code coverage from Babel tests
* Configure nyc correctly for Babel test coverage
* Guard against nyc config conflicts if Babel switches to nyc in the future
* Move .nyc_output from Babel build dir to root
* Use .gitattributes to ignore files with weird newlines
* [Flow] Make parameter names in function types optional
* [Flow] Anonymous function types with single params can omit parens
* [Flow] Optional names for object indexer keys
* Add noAnonFunctionType explicitly to state
* Adjust gitattributes as files have been fixed
* Increase test coverage
* Test for error when binding `this` in destructuring pattern
* Ignore coverage of inAsync check in parseAwait - already checked externally
* Ignore coverage of default case in checkPropClash
* Remove unused parameter isAsync from parseParenAndDistinguishExpression
* Ignore coverage of an `else` branch in flowParseTypeParameterDeclaration
* Flow: remove unused parameters to flowParseTypeAnnotatableIdentifier
* Flow: ignore coverage of pass-through throw statement in parseConditional
* Flow: Add test for error on property with type param
* Flow: ignore coverage of pass-through throw statements in parseMaybeAssign, parseArrow
* Add test for error on XML-style comment in module code
* Update test for error on method in object pattern
* Test for error: "Only '=' operator can be used for specifying default value"
* Property variance type annotations for Flow plugin
Non-method properties and indexers of object types, declare class, and
interfaces can be "positive" or "negative." Class fields, but again not
methods, can also have variance.
This PR generalizes the variance annotations for type parameters into a
new node type, and reuses that node for those properties.
The code for object types is reused for interfaces and declare classes.
The changes there are straightfoward.
The code for class fields is reused for object literals, which do not
support variance annotations (currently). This code is a bit sketchy,
because we always parse variance annotations in the `parsePropertyName`
extension, then error in a the subsequent parse phase for object
literals (`parseObjPropValue`) or class methods (`parseClassMethod`).
* Remove bogus unreachable code, clarify variance parsing conditional
* Don't use a new node type for variance annotations
Adding a new node type, specifically changing the TypeParameter node's
variance property to be node-valued, is a breaking change. We might
choose to make this breaking change in a later version.
* s/start/variancePos
Expanding on #150, this allows `unexpected()` to accept the expected token type instead of a message string.
This overload is then used in a couple more places (that independently implement a logic similar to `expect()`'s) to construct an `Unexpected token, expected FOO` message.
I also noticed that there was missing test coverage for builtin types,
so I added a test for that, which includes the newly added type as well
as the other existing types.
* Fix parsing object rest
This makes object-rest-spread behave according to spec and only
allow one rest operator and enforces it to be the last
param in the object.
Also move all object-rest-spread tests to a own folder.
* Show nicer error messages
* Rephrase "assigning/binding to rvalue" error messages with context (#119)
* Fix code style in parser/lval.js
* istanbul ignore some unused branches in parser/lval.js
* Fix code style again in parser/lval.js
* Slightly simplify logic
* Implement ES2016 check for simple parameter list in strict mode
See e.g. ECMA-262 7.0 14.1.2:
> It is a Syntax Error if ContainsUseStrict of FunctionBody is true and
> IsSimpleParameterList of FormalParameters is false.
Similar clauses cover arrow functions, generator functions, methods, and
generator methods, as well as async functions and async arrow functions.
* exact object type annotations for Flow plugin
* Couple tweaks per suggestions
* s/==/===/
* add test for unexpected token in flowObjectType Semicolon
This makes declare class extends behave the same way as in flow
The ast-token after the extends keyword, might be either Identifier or
QualifiedTypeIdentifier
To do that this commits splits the parseGenericType into two functions,
one for parsing genericType and on for qualifiedTypeIdentifier
Flow's "toAssignable" override wasn't calling the inner function,
resulting in the destructuring in an AssignmentPattern not having the
node type changed from ObjectExpression to ObjectPattern, resulting in
"Binding rvalue" thrown from "checkLVal()"
* This removes the exponentiationOperator as it is now in es2016
* Remove from tests
* Remove asyncFunctions and restructure test dirs
* Remove trailingFunctionCommas
We do not clone arrays in lookahead() but comments were added
to leading/trailing arrays during lookahead, leading to leak to the next next() call.
Also extracted parsing of JSXSpreadChild to own parse function.
This commit e6c11a0 (#19) made a big performance regression.
The reason was that parseConditional was always cloning the current state
even if no question mark (potential conditional or flow-optional
token) was at the current position.
Simply checking if questionmark matches the current token solves the problem.
Fixes#62
The cloning caused comments that where added to the original node to be persisted into
the cloned node.
Espree/Acorn does not have any cloning, that's why it is working there.
This change omits comments when cloning, as removing the cloning
causes tests in babel to fail.
The primary goal of this commit is to add the ability to parse type parameter
declarations with defaults, like `type Foo<T = string> = T`. While I was in the
code, I fixed a few small things, like
* Type parameter declarations need 1 or more type parameters.
* The existential type `*` is not a valid type parameter.
* The existential type `*` is a primary type
* The param list for type parameter declarations now consists of
`TypeParameter` nodes
This fixes an issue that comments were added as leading comments
to expressions, which are not immediately folowing the comment.
This was also reported and fixed in espree, and is basically a port to
babylon. eslint/espree#256
this also fixes an issue in babel-eslint with certain rules babel/babel-eslint#289
The fix includes creating a new method on the parser called `parseArrow`.
This new function by default only checks if current position matches an
arrow. If it does returns the `node` otherwise `undefined`.
The flow plugin can then extend this function and correctly parse the typeAnnotation
and add it to the node.
With this change, in the flow plugin there is no need anymore to extend
`parseParenAndDistinguishExpression` and the arrow handling in `parseParenItem`
could also be removed, because it is all handled now in `parseArrow`.
Some existing tests were failing, because `extra->parentesized` is now missing,
but this is correct as it is now inline with parsing without flow annotation. No extra
is added for arrow function without type annotations.
In the expression-parser `this.next()` was replaced by a more specific
`this.expect(tt.parenL)`.
This syntax allows you to specify whether a type variable can appear in
a covariant or contravariant position, and is super useful for, say,
Promise.
Right now this is hacked in jankily, but in the next major release we
should stop using Identifier nodes for type parameters.
An interface export is just like a type export. In fact, it's a syntax affordance which makes the following equivalent:
```javascript
interface I_ { ... }
export type I = I_;
```
```javascript
export interface I { ... }
```
See facebook/flow#1145
This has been a feature in Flow for a long time (couldn't easily find a
specific commit adding this). Interfaces are basically undocumented, though, so
it's easy to see how this was missed.
For example:
var foo = function () {
"use strict";
"use strict";
// there is inside of strict mode,
// so `0123` (octal number) occurs a syntax error.
};
// there is outside of strict mode,
0123; // so left is valid syntax.
// however:
// SyntaxError: Invalid number (8:0)
I fixed it and add the test case.
Removed `@flow` annotation from files that don't actually pass Flow check at the moment. These will be added back file by file once the files are properly converted to use Flow.
Closes#3064
I'm extremely stupid and didn't commit as I go. To anyone reading this
I'm extremely sorry. A lot of these changes are very broad and I plan on
releasing Babel 6.0.0 today live on stage at Ember Camp London so I'm
afraid I couldn't wait. If you're ever in London I'll buy you a beer
(or assorted beverage!) to make up for it, also I'll kiss your feet and
give you a back massage, maybe.
- The visitor keys for `ObjectTypeAnnotation`s were incorrect so those nodes weren't being traversed so comments weren't attached for them.
- The type parser wasn't eating the semicolons for the nodes so the `end` location of each of the type properties wasn't accurate which threw off the code generation newline algorithm.
- Type properties hadn't been given the `UserWhitespacable` alias.
This completely changes the interface, and removes most of the complexity
in the old tokenizer interface (jump-to-position was removed, since it is
all kinds of unreliable given the new tokenizer context system).
Makes almost everything in acorn.js a method of this object.
Performance is not significantly affected on a modern V8. Makes the
code reentrant and allows us to more easily expose more methods
externally in the future.
On the other hand, the proliferation of `this.` is unfortunate.
Now identifiers and strings even with escaped chars are read
in optimized way by reading entire chunks delimited by escape
chars (and not bailing to deopt mode on first one).
Avoid need for:
* extra `templates` array in favor of new `tokContext`;
* special location handling for first & last template elements;
* separate `_templateContinued` token in favor of same `_template`.
Adds:
* token types for backQuote and dollarBraceL instead of skipping them
so they can be handled (i.e. highlighted differently).
* Parsing assignables without extra transform step when possible (speed-up).
* Added support for shorthand defaults in such certain contexts (issue #181).
Conflicts:
acorn.js
acorn_loose.js
* Parsing assignables without extra transform step when possible (speed-up).
* Added support for shorthand defaults in such certain contexts (issue #181).
Define Program node extent to be the whole program, make
both parser and the tests conform to this.
Fix a bunch of bugs in the loose parser's handling of corner
cases.
Issue #151
* Added support for acorn_loose and grouped log to web-driver.
* Removed unused copy-pasted `parseTemplate` from loose parser.
* Throw non-SyntaxError errors immediately (as those are generic).
* Tokens are now instances of single exported constructor Token.
* Token objects are compatible with Esprima (only `type` format is different).
* Added token.loc in format of node.loc (Mozilla).
* Deprecated token.startLoc & token.endLoc.
* Updated comment generation example.
Also added ability to pass arrays in `onToken`/`onComment` where
tokens/comments will be collected in Esprima's format so you can
simply pass those arrays to `escodegen.attachComments`.
Updated docs and comment attachment example.
* Fixed `onToken` & `tokenize` to return `startLoc` & `endLoc`
in token object only when `options.locations` is `true`.
* Fixed `onToken` tests.
* Added example for generating comments with escodegen.
Possible dev relic.
readToken_slash currently does not have any arguments and does not appear to look at arguments. All existing tests pass after removal of extraneous argument while calling readToken_slash.
http://wiki.ecmascript.org/doku.php?id=harmony:rest_parameters
The final parameter to a function is a rest parameter if it is
prefixed by "...". FunctionExpression and FunctionDeclaration
nodes have a new "rest" property that is null if there is no
rest parameter, or contains an Identifer for the parameter.
https://developer.mozilla.org/en-US/docs/SpiderMonkey/Parser_API#Functions
Implemented by adding a new token, `_ellipsis`, which consists of
three dots. Modified the body of parseFunction to allow a single
rest parameter at the end of an argument list. Both the token and
the rest parameter require `options.ecmaVersion` >= 6, otherwise
three dots are tokenized as three dots.
Before this the ast produced by parse_dammit crashed in the following
code, as Uglify correctly noticed that f."" is invalid.
sample = 'f."';
loose = require('acorn/acorn_loose');
uglify = require('uglify-js');
out = new uglify.OutputStream();
ast = loose.parse_dammit(sample);
ast = uglify.AST_Node.from_mozilla_ast(ast);
ast.print(out);
// TypeError: Cannot call method 'toString' of undefined
// member_exp.computed = false && member_exp.property == ""
console.log(out.toString());
After this the round-tripped AST looks like: `t.✖;"";`, which is
consistent with how `foo.{` is parsed.
I also considered making it parse as t[""], but as this only turns up in
the wild when people try to use multiline strings, I felt it was better
to be obviously wrong.
Both readString and skipLineComment considered 8232/8233 as eol, but skipSpace itself would not increment the line counters if they were found.
Previously 8232/8233 were listed in nonASCIIwhitespace, but since that is only used within skipSpace and those values are checked separately, they could be removed from nonASCIIwhitespace.
Just being consistent.
In every other place where a between comparison is done, the lower limit is on the left. It's a whole lot easier to see it's a between comparison when the limits are in order.
When the continued expression sat on column 1 after a non-whitespace char,
the heuristic would consider it the start of the line, even though it wasn't.
Issue marijnh/tern#141
Dedented tokens should only end an expression if they are actually the first
token on the line.
This to prevent code like this from going wrong:
x = (function(..) {
blah();
})(); // <-- indented same as start of expression
My initial idea, that client code would constantly need to access the individual
walker functions directly, isn't actually the case. This prevents unnecessary copying
of other interface functions into walkers.
When setting the .prototype.source the sourceFile variable is undefined, and
setting the sourceFile option doesn't change the .source property on the
prototype anymore.
By setting the .source property inside the node_loc_t constructor, the correct
sourceFile is set in the loc object.
In the generated ast, "null"/"true"/"false" are "Literal" nodes.
As every "Literal" node has a 'raw' property,
When i am doing something with the ast using python,
the 3 "Literal"s caused some problem.
make the 3 "Literal"s have 'raw' property.
This way, composite expressions that they are part of won't get bogus
unsyntactic substrings as their range (i.e. in '(1)+1', the binop expression
would span '1)+1').
Closes#14
- if `program` is given, it'll be used as the toplevel node, instead of
creating a new node, and statements will be added to its body
- if `sourceFile` is given and `locations` is ON, it'll set the `source`
property in every node's `loc`.
Checking for `\r\n?` is redundant with the `|[\n\r\u2028\u2029]`, better straighten the regexp and check for `\r\n|[\n\r\u2028\u2029]`. This might even be a itsy bitsty bit faster.
For issue references: Add a comma-separated list of a [closing word](https://help.github.com/articles/closing-issues-via-commit-messages/) followed by the ticket number fixed by the PR. It should be underlined in the preview if done correctly.
@@ -8,11 +8,12 @@ For issue references: Add a comma-separated list of a [closing word](https://hel
| Q | A <!--(Can use an emoji 👍) -->
| ------------------------ | ---
| Fixed Issues? | `Fixes #1, Fixes #2` <!-- remove the (`) quotes to link the issues -->
| Patch: Bug Fix? |
| Major: Breaking Change? |
| Minor: New Feature? |
| Patch: Bug Fix? |
| Major: Breaking Change? |
| Minor: New Feature? |
| Tests Added + Pass? | Yes
| Documentation PR | <!-- If so, add `[skip ci]` to your commit message to skip CI -->
| Any Dependency Changes? |
| Any Dependency Changes? |
| License | MIT
<!-- Describe your changes below in as much detail as possible -->
> Before contributing, please read our [code of conduct](https://github.com/babel/babel/blob/master/CODE_OF_CONDUCT.md).
Contributions are always welcome, no matter how large or small.
Contributions are always welcome, no matter how large or small. Before
contributing, please read the
[code of conduct](https://github.com/babel/babel/blob/master/CODE_OF_CONDUCT.md).
## Not sure where to start?
- If you aren't just making a documentation change, you'll probably want to learn a bit about a few topics.
- [ASTs](https://en.wikipedia.org/wiki/Abstract_syntax_tree) (Abstract Syntax Tree): The Babel AST [spec](https://github.com/babel/babylon/blob/master/ast/spec.md) is a bit different from [ESTree](https://github.com/estree/estree). The differences are listed [here](https://github.com/babel/babylon#output).
- [ASTs](https://en.wikipedia.org/wiki/Abstract_syntax_tree) (Abstract Syntax Tree): The Babel AST [spec](https://github.com/babel/babel/blob/master/packages/babylon/ast/spec.md) is a bit different from [ESTree](https://github.com/estree/estree). The differences are listed [here](https://github.com/babel/babel/tree/master/packages/babylon#output).
- Check out [`/doc`](https://github.com/babel/babel/tree/master/doc) for information about Babel's internals
- Check out [the Babel Plugin Handbook](https://github.com/thejameskyle/babel-handbook/blob/master/translations/en/plugin-handbook.md#babel-plugin-handbook) - core plugins are written the same way as any other plugin!
- Check out [AST Explorer](http://astexplorer.net/#/scUfOmVOG5) to learn more about ASTs or make your own plugin in the browser
- When you feel ready to jump into the Babel source code, a good place to start is to look for issues tagged with [help wanted](https://github.com/babel/babel/labels/help%20wanted) and/or [good first issue](https://github.com/babel/babel/labels/good%20first%20issue).
- Follow along with what we are working on by joining our Slack, following our announcements on [Twitter](https://twitter.com/babeljs), and reading (or participating!) in our [meeting notes](https://github.com/babel/notes).
- Follow along with what we are working on by joining our [Slack](https://babeljs.slack.com) (you can sign-up [here](https://slack.babeljs.io/)
for an invite), following our announcements on [Twitter](https://twitter.com/babeljs), and reading (or participating!) in our [meeting notes](https://github.com/babel/notes).
- Check out our [website](http://babeljs.io/) and the [repo](https://github.com/babel/website)
## Chat
Feel free to check out the `#discussion`/`#development` channels on our [Slack](https://slack.babeljs.io). Some of us are always online to chat!
Feel free to check out the `#discussion`/`#development` channels on our [Slack](https://slack.babeljs.io) (you can sign-up [here](https://slack.babeljs.io/) for an invite). Some of us are always online to chat!
## Developing
**Note:** Versions `< 5.1.10` can't be built.
Babel is built for Node 4 and up but we develop using Node 8 and yarn. You can check this with `node -v`.
Babel is built for Node 6 and up but we develop using Node 8 and yarn. You can check this with `node -v`.
Make sure that Yarn is installed with version >= `0.28.0`.
Installation instructions can be found here: https://yarnpkg.com/en/docs/install.
@@ -115,8 +116,8 @@ $ TEST_ONLY=babel-cli make test
`TEST_ONLY` will also match substrings of the package name:
```sh
# Run tests for the babel-plugin-transform-classes package.
$ TEST_ONLY=es2015-class make test
# Run tests for the @babel/plugin-transform-classes package.
$ TEST_ONLY=babel-plugin-transform-classes make test
```
Use the `TEST_GREP` variable to run a subset of tests by name:
@@ -139,6 +140,12 @@ $ TEST_DEBUG=true make test
You can combine `TEST_DEBUG` with `TEST_GREP` or `TEST_ONLY` to debug a subset of tests. If you plan to stay long in the debugger (which you'll likely do!), you may increase the test timeout by editing [test/mocha.opts](https://github.com/babel/babel/blob/master/test/mocha.opts).
To overwrite any test fixtures when fixing a bug or anything, add the env variable `OVERWRITE=true`
```sh
$ OVERWRITE=trueTEST_ONLY=babel-plugin-transform-classes make test-only
```
To test the code coverage, use:
```sh
@@ -146,7 +153,6 @@ $ BABEL_ENV=cov make build
$ ./scripts/test-cov.sh
```
#### Troubleshooting Tests
In case you're not able to reproduce an error on CI locally, it may be due to
@@ -162,43 +168,43 @@ In case you're locally getting errors which are not on the CI, it may be due to
Most packages in [`/packages`](https://github.com/babel/babel/tree/master/packages) have a `test` folder, however some tests might be in other packages or in [`/packages/babel-core`](https://github.com/babel/babel/tree/master/packages/babel-core/test/fixtures).
#### `babel-plugin-x`
#### `@babel/plugin-x`
All the Babel plugins (and other packages) that have a `/test/fixtures` are written in a similar way.
For example, in [`babel-plugin-transform-exponentiation-operator/test`](https://github.com/babel/babel/tree/master/packages/babel-plugin-transform-exponentiation-operator/test):
For example, in [`@babel/plugin-transform-exponentiation-operator/test`](https://github.com/babel/babel/tree/master/packages/babel-plugin-transform-exponentiation-operator/test):
- There is an `index.js` file. It imports our [test helper](https://github.com/babel/babel/tree/master/packages/babel-helper-plugin-test-runner). (You don't have to worry about this).
- There can be multiple folders under [`/fixtures`](https://github.com/babel/babel/tree/master/packages/babel-plugin-transform-exponentiation-operator/test/fixtures)
- There is an [`options.json`](https://github.com/babel/babel/blob/master/packages/babel-plugin-transform-exponentiation-operator/test/fixtures/exponentian-operator/options.json) file whose function is similar to a `.babelrc` file, allowing you to pass in the plugins and settings you need for your tests.
- For this test, we only need the relevant plugin, so it's just `{ "plugins": ["@babel/transform-exponentiation-operator"] }`.
- For this test, we only need the relevant plugin, so it's just `{ "plugins": ["@babel/plugin-transform-exponentiation-operator"] }`.
- If necessary, you can have an `options.json` with different options in each subfolder.
- In each subfolder, you can organize your directory structure by categories of tests. (Example: these folders can be named after the feature you are testing or can reference the issue number they fix)
- Generally, there are two kinds of tests for plugins
- The first is a simple test of the input and output produced by running Babel on some code. We do this by creating an [`actual.js`](https://github.com/babel/babel/blob/master/packages/babel-plugin-transform-exponentiation-operator/test/fixtures/exponentian-operator/binary/actual.js) file and an [`expected.js`](https://github.com/babel/babel/blob/master/packages/babel-plugin-transform-exponentiation-operator/test/fixtures/exponentian-operator/binary/expected.js) file.
- If you need to expect an error, you can ignore creating the `expected.js` file and pass a new `throws` key to the `options.json` that contains the error string that is created.
- The first is a simple test of the input and output produced by running Babel on some code. We do this by creating an [`input.js`](https://github.com/babel/babel/blob/master/packages/babel-plugin-transform-exponentiation-operator/test/fixtures/exponentian-operator/binary/input.js) file and an [`output.js`](https://github.com/babel/babel/blob/master/packages/babel-plugin-transform-exponentiation-operator/test/fixtures/exponentian-operator/binary/output.js) file. This kind of test only works in sub-subdirectories of `/fixtures`, i.e. `/fixtures/exponentian-operator/binary/input.js` and **not**`/fixtures/exponentian-operator/input.js`.
- If you need to expect an error, you can ignore creating the `output.js` file and pass a new `throws` key to the `options.json` that contains the error string that is created.
- The second and preferred type is a test that actually evaluates the produced code and asserts that certain properties are true or false. We do this by creating an [`exec.js`](https://github.com/babel/babel/blob/master/packages/babel-plugin-transform-exponentiation-operator/test/fixtures/exponentian-operator/comprehensive/exec.js) file.
In an actual/expected test, you simply write out the code you want transformed in `actual.js`.
In a fixture test, you simply write out the code you want transformed in `input.js`.
```js
// actual.js
// input.js
2**2;
```
and the expected output after transforming it with your `options.json` in `expected.js`.
and the expected output after transforming it with your `options.json` in `output.js`.
```js
// expected.js
// output.js
Math.pow(2,2);
```
In an `exec.js` test, we run or check that the code actually does what it's supposed to do rather than just check the static output.
```js
// exec.js
assert.equal(8,2**3);
assert.equal(24,3*2**3);
expect(2**3).toBe(8);
expect(3*2**3).toBe(24);
```
If you need to check for an error that is thrown you can add to the `options.json`
@@ -206,8 +212,8 @@ If you need to check for an error that is thrown you can add to the `options.jso
"throws":"@babel/plugin-proposal-object-rest-spread currently only accepts a boolean option for useBuiltIns (defaults to false)"
}
```
@@ -220,20 +226,45 @@ If the test requires a minimum Node version, you can add `minNodeVersion` (must
}
```
#### `babylon`
Writing tests for Babylon is very
similar to the other packages.
Inside the `packages/babylon/tests/fixtures` folder are categories/groupings of test fixtures (es2015, flow,
etc.). To add a test, create a folder under one of these groupings (or create a new one) with a
descriptive name, and add the following:
* Create an `input.js` file that contains the code you want Babylon to parse.
* Add an `output.json` file with the expected parser output. For added convenience, if there is no `output.json` present, the test runner will generate one for you.
After writing tests for babylon, just build it by running:
```sh
$ make build
```
Then, to run the tests, use:
```sh
$ TEST_ONLY=babylon make test-only
```
#### Bootstrapping expected output
For both `babel-plugin-x` and `babylon`, you can easily generate an `expected.js`/`expected.json` automatically by just providing `actual.js` and running the tests as you usually would.
For both `@babel/plugin-x` and `babylon`, you can easily generate an `output.js`/`output.json` automatically by just providing `input.js` and running the tests as you usually would.
```
// Example
- babylon
- test
- fixtures
- comments
- basic
- block-trailing-comment
- actual.js
- expected.json (will be generated if not created)
- packages
- babylon
- test
- fixtures
- comments
- basic
- block-trailing-comment
- input.js
- output.json (will be generated if not created)
```
### Debugging code
@@ -255,7 +286,7 @@ To include the changes, we have to make sure to build Babel:
$ make build
```
Next, we need to execute `Generator.generate()`, which can be achieved by running a test case in the `babel-generator` package.
Next, we need to execute `Generator.generate()`, which can be achieved by running a test case in the `@babel/generator` package.
For example, we can run the test case that tests the generation of class declarations:
```bash
@@ -263,7 +294,6 @@ $ TEST_DEBUG=true TEST_GREP=ClassDeclaration make test-only
./scripts/test.sh
Debugger listening on port 9229.
Warning: This is an experimental feature and could change at any time.
To start debugging, open the following URL in Chrome:
@@ -273,9 +303,21 @@ The debugger starts at the first executed line of code, which is Mocha's first l
Click _Resume script execution_ <img src="https://i.imgur.com/TmYBn9d.png" alt="Resume script execution button." width="16"> to jump to the set breakpoint.
Note that the code shown in Chrome DevTools is compiled code and therefore differs.
- Create a new issue that describes the proposal (ex: [#538](https://github.com/babel/babylon/issues/538)). Include any relevant information like proposal repo/author, examples, parsing approaches, meeting notes, presentation slides, and more.
- The pull request should include:
- [ ] An update to the [plugins](https://github.com/babel/babel/tree/master/packages/babylon#plugins) part of the readme. Add a new entry to that list for the new plugin flag (and link to the proposal)
- [ ] If any new nodes or modifications need to be added to the AST, update [ast/spec.md](https://github.com/babel/babel/bloc/master/packages/babylon/ast/spec.md)
- [ ] Make sure you use the `this.hasPlugin("plugin-name-here")` check in Babylon so that your new plugin code only runs when that flag is turned on (not default behavior)
- [ ] Add failing/passing tests according to spec behavior
- Compiler environment support ([doc/design/compiler-environment-support.md](https://github.com/babel/babel/blob/master/doc/design/compiler-environment-support.md))
Babel is community-driven and thus mostly maintained by a group of [volunteers](https://babeljs.io/team). It has a lot of [companies and projects](http://babeljs.io/users) using it but almost no sponsors/people funded to work on it. If you'd like to help maintain the future of the project, please consider:
Babel is a community-driven project used by many companies and projects, and is maintained by a group of [volunteers](https://babeljs.io/team). If you'd like to help support the future of the project, please consider:
- Giving developer time on the project. (Message us on [Twitter](https://twitter.com/babeljs) or [Slack](slack.babeljs.io))
-[Giving funds by becoming a backer/sponsor on OpenCollective](https://opencollective.com/babel)
- Giving developer time on the project. (Message us on [Twitter](https://twitter.com/babeljs) or [Slack](https://slack.babeljs.io/) for guidance!)
- Giving funds by becoming a sponsor (see below)!
## Open Collective Sponsors
Become a sponsor and get your logo on our README on Github with a link to your site. [[Become a sponsor](https://opencollective.com/babel#sponsor)]
@@ -50,11 +100,6 @@ Babel is a tool that helps you write code in the latest version of JavaScript. W
Try it out at our [REPL](https://babeljs.io/repl/build/master#?code_lz=NoRgNATGDMC6B0BbAhgBwBQDsAEBeAfNjgNTYgCUA3EA&lineWrap=true&presets=es2015%2Ces2016%2Ces2017&version=7.0.0-beta.2).
- [FAQ](#faq)
- [Backers](#backers)
- [Sponsors](#sponsors)
- [License](#license)
## FAQ
### Who maintains Babel?
@@ -63,19 +108,23 @@ Mostly a handful of volunteers! Please check out our [team page](https://babeljs
### Looking for support?
For questions and support please visit join our [Slack Community](https://slack.babeljs.io/), ask a question on [Stack Overflow](http://stackoverflow.com/questions/tagged/babeljs), or ping us on [Twitter](https://twitter.com/babeljs/).
For questions and support please visit join our [Slack Community](https://slack.babeljs.io/) (you can sign-up [here](https://slack.babeljs.io/) for an invite), ask a question on [Stack Overflow](https://stackoverflow.com/questions/tagged/babeljs), or ping us on [Twitter](https://twitter.com/babeljs).
### Is there a Babel song?
I'm so glad you asked: [Hallelujah —— In Praise of Babel](SONG.md) by [@angus-c](https://github.com/angus-c). Tweet us your recordings!
### Where are the docs?
Check out our website: [babeljs.io](http://babeljs.io/), and report issues/features at [babel/website](https://github.com/babel/website/issues).
Check out our website: [babeljs.io](https://babeljs.io/), and report issues/features at [babel/website](https://github.com/babel/website/issues).
### Want to report a bug or request a feature?
Please read through our [CONTRIBUTING.md](https://github.com/babel/babel/blob/master/CONTRIBUTING.md) and fill out the issue template at [babel/issues](https://github.com/babel/babel/issues)!
Please read through our [CONTRIBUTING.md](CONTRIBUTING.md) and fill out the issue template at [babel/issues](https://github.com/babel/babel/issues)!
### Want to contribute to Babel?
Check out our [CONTRIBUTING.md](https://github.com/babel/babel/blob/master/CONTRIBUTING.md) to get started with setting up the repo.
Check out our [CONTRIBUTING.md](CONTRIBUTING.md) to get started with setting up the repo.
- If you have already joined Slack, join our [#development](https://babeljs.slack.com/messages/development) channel and say hi!
- Check out the issues with the [good first issue](https://github.com/babel/babel/labels/good%20first%20issue) and [help wanted](https://github.com/babel/babel/labels/help%20wanted) label. We suggest also looking at the closed ones to get a sense of the kinds of issues you can tackle.
@@ -84,78 +133,8 @@ Check out our [CONTRIBUTING.md](https://github.com/babel/babel/blob/master/CONTR
### How is the repo structured?
The Babel repo is managed as a [monorepo](https://github.com/babel/babel/blob/master/doc/design/monorepo.md) that is composed of many [npm packages](/packages#readme).
## Backers
Support us with a monthly donation and help us continue our activities. [[Become a backer](https://opencollective.com/babel#backer)]
The [AST specification](https://github.com/babel/babylon/blob/master/ast/spec.md) has been moved to the Babylon repo, `babel/babylon`.
The [AST specification](https://github.com/babel/babel/blob/master/packages/babylon/ast/spec.md) has been moved to the Babylon package, `packages/babylon`.
- Update compat table to fix two small issues ([#445](https://github.com/babel/babel-preset-env/pull/445)) (@danez)
ES2015 destructuring is not fully supported in Edge 15 and the polyfill required again. `es6.math.imul` is supported on Android as of version 4.4
- Add polyfills for ES6 static Object methods ([#441](https://github.com/babel/babel-preset-env/pull/441)) (@danez)
Functions such as `Object.keys`, `Object.freeze`, ... do already exist in ES5, but their behaviour changed in ES2015. `babel-preset-env` with `builtIns: true` now adds the core-js polyfills for this methods if the browser only supports the ES5 variant of the method (like IE11 for example)
- Normalize module format of plugins/built-ins data ([#376](https://github.com/babel/babel-preset-env/pull/376)) (@rtsao)
## v1.6.0 (2017-07-04)
### :rocket: New Feature
- Bump compat-table for node8 support ([#363](https://github.com/babel/babel-preset-env/pull/363)) (@existentialism)
We updated our mappings to support native trailing function commas and string paddings in Node.js 8+.
### :bug: Bug Fix
- Handle `chromeandroid` browserslist value ([#367](https://github.com/babel/babel-preset-env/pull/367)) (@yavorsky)
We added support for using browserslist's `chromeandroid` in `targets`.
Our plugin data was missing a mapping for the `transform-duplicate-keys` plugin which caused it to never be included. (s/o to @Timer for the report!)
### :memo: Documentation
- Clarify reasons for the uglify option in README.md ([#188](https://github.com/babel/babel-preset-env/pull/188)) (@mikegreiling)
## v1.2.0 (2017-03-03)
### :rocket: New Feature
- Add uglify as a target ([#178](https://github.com/babel/babel-preset-env/pull/178)) (@yavorsky)
Support for `uglify` as a target is now available! This will enable all plugins and, as a result, fully compiles your code to ES5. Note, that useBuiltIns will work as before, and only the polyfills that your other target(s) need will be included.
```json
{
"presets":[
["env",{
"targets":{
"chrome":55,
"uglify":true
},
"useBuiltIns":true,
"modules":false
}]
]
}
```
### :bug: Bug Fix
- Respect older versions in invert equals map ([#180](https://github.com/babel/babel-preset-env/pull/180)) (@danez)
Fixes a number of bugs that caused some incorrect and/or missing environment data when parsing `compat-table`.
## v1.1.11 (2017-03-01)
This release primarily upgrades `compat-table`, which adds support for async on Node 7.6!
- Add electron version exception test ([#176](https://github.com/babel/babel-preset-env/pull/176)) (@existentialism)
## v1.1.10 (2017-02-24)
### :bug: Bug Fix
- Drop use of lodash/intersection from checkDuplicateIncludeExcludes ([#173](https://github.com/babel/babel-preset-env/pull/173)) (@existentialism)
## v1.1.9 (2017-02-24)
### :bug: Bug Fix
- Add tests for debug output ([#156](https://github.com/babel/babel-preset-env/pull/156)) (@existentialism)
Since we've (mostly @yavorsky) have fixed a number of bugs recently with the `debug` option output, we added the ability to assert stdout matches what we expect. Read the updated [CONTRIBUTING.md](https://github.com/babel/babel-preset-env/blob/master/CONTRIBUTING.md#testing-the-debug-option) for more info.
- Update compat-table, build data ([#135](https://github.com/babel/babel-preset-env/pull/135)) (@hzoo)
## v1.1.8 (2017-01-10)
### :bug: Bug Fix
- Debug: Transformations before logs. ([#128](https://github.com/babel/babel-preset-env/pull/128)) (@yavorsky)
Makes sure that all transformations on `targets` (such as `exclude`/`include`) are run before logging out with the `debug` option. Fixes ([#127](https://github.com/babel/babel-preset-env/issues/127)).
The new `exclude`/`include` options weren't working correctly for built-ins. ([#102](https://github.com/babel/babel-preset-env/pull/102)).
Also fixes an issue with debug option.
## v1.1.1 (2016-12-13)
### :bug: Bug Fix
Regression with the previous release due to using `Object.values` (ES2017). This wasn't caught because we are using babel-register to run tests and includes polyfills so it didn't fail on CI even though we have Node 0.10 as an env. Looking into fixing this to prevent future issues.
## v1.1.0 (2016-12-13)
### :rocket: New Feature
- Add `exclude` option, rename `whitelist` to `include` ([#89](https://github.com/babel/babel-preset-env/pull/89)) (@hzoo)
Example:
```js
{
"presets":[
["env",{
"targets":{
"browsers":["last 2 versions","safari >= 7"]
},
"include":["transform-es2015-arrow-functions"],
"exclude":[
"transform-regenerator",
"transform-async-to-generator",
"map"
],
"useBuiltIns":true
}]
]
}
```
`"exclude": ["transform-regenerator"]` doesn't transform generators and removes `regeneratorRuntime` from being imported.
`"exclude": ["transform-async-to-generator"]` doesn't use the built-in async-to-gen transform so you can use something like [fast-async](https://github.com/MatAtBread/fast-async).
`"exclude": ["map"]` doesn't include the `Map` polyfill if you know you aren't using it in your code (w/ `useBuiltIns`). (We will figure out a way to automatically do this [#84](https://github.com/babel/babel-preset-env/issues/84)).
If you pass a wrong plugin it will error: valid options for `include/exclude` are in [/data/plugin-features.js](https://github.com/babel/babel-preset-env/blob/master/data/plugin-features.js) and [/data/built-in-features.js](https://github.com/babel/babel-preset-env/blob/master/data/built-in-features.js) (without the `es6.`)
### :house: Internal
- Optimize result filtration. ([#77](https://github.com/babel/babel-preset-env/pull/77)) (@yavorsky)
- Update eslint config to align with other babel projects ([#79](https://github.com/babel/babel-preset-env/pull/79)) (@baer)
- Update pathnames to avoid uppercase ([#80](https://github.com/babel/babel-preset-env/pull/80)) (@baer)
- Refactor build data for clarity/consistency ([#81](https://github.com/babel/babel-preset-env/pull/81)) (@baer)
- Update linting rules to cover all js ([#82](https://github.com/babel/babel-preset-env/pull/82)) (@baer)
- Cleanup lib before rebuilding ([#87](https://github.com/babel/babel-preset-env/pull/87)) (@baer)
- Move linting dependency to be dev only ([#88](https://github.com/babel/babel-preset-env/pull/88)) (@baer)
A way to apply `babel-preset-env` for polyfills (via `"babel-polyfill"``).
> This option will apply a new Babel plugin that replaces `require("babel-polyfill")` with the individual requires for `babel-polyfill` based on the target environments.
Install
```
npm install babel-polyfill --save
```
In
```js
import "babel-polyfill"; // create an entry js file that contains this
> Also looking to make an easier integration point via Webpack with this method. Please reach out if you have ideas!
---
* Support [Electron](http://electron.atom.io/) ([#55](https://github.com/babel/babel-preset-env/pull/55)) ([@paulcbetts](https://github.com/paulcbetts))
Electron is also an environment, so [Paul went ahead](https://twitter.com/paulcbetts/status/804507070103851008) and added support for this!
> Currently we are manually updating the data in [/data/electron-to-chromium.js](https://github.com/babel/babel-preset-env/blob/master/data/electron-to-chromium.js), but [@kevinsawicki](https://github.com/kevinsawicki) says we could generate the data from [atom-shell/dist/index.json](https://gh-contractor-zcbenz.s3.amazonaws.com/atom-shell/dist/index.json) as well! (Someone should make a PR :smile:)
## v0.0.9 (2016-11-24)
### :rocket: New Feature
* Support Opera ([#48](https://github.com/babel/babel-preset-env/pull/48)) (Henry Zhu)
Was as simple as modifying the chrome version and subtracting 13! (so chrome 54 = opera 41)
```js
{
"presets": [
["env", {
"targets": {
"opera": 41
}
}]
]
}
```
## v0.0.8 (2016-11-16)
### :nail_care: Polish
* Only print the debug info once ([#46](https://github.com/babel/babel-preset-env/pull/46) (Henry Zhu)
When using the `debug` option it was printing the data for each file processed rather than once.
```js
{
"presets": [
["env", {
"debug": true
}]
]
}
```
## v0.0.7 (2016-11-02)
### :rocket: New Feature
* hardcode a current node version option ([#35](https://github.com/babel/babel-preset-env/pull/35)) (Henry Zhu)
> A Babel preset that compiles [ES2015+](https://github.com/tc39/proposals/blob/master/finished-proposals.md) down to ES5 by automatically determining the Babel plugins and polyfills you need based on your targeted browser or runtime environments.
```sh
npm install @babel/preset-env --save-dev
```
Without any configuration options, @babel/preset-env behaves exactly the same as @babel/preset-latest (or @babel/preset-es2015, @babel/preset-es2016, and @babel/preset-es2017 together).
```json
{
"presets":["@babel/env"]
}
```
You can also configure it to only include the polyfills and transforms needed for the browsers you support. Compiling only what's needed can make your bundles smaller and your life easier.
This example only includes the polyfills and code transforms needed for the last two versions of each browser, and versions of Safari greater than or equal to 7. We use [browserslist](https://github.com/ai/browserslist) to parse this information, so you can use [any valid query format supported by browserslist](https://github.com/ai/browserslist#queries).
```json
{
"presets":[
["@babel/env",{
"targets":{
"browsers":["last 2 versions","safari >= 7"]
}
}]
]
}
```
Similarly, if you're targeting Node.js instead of the browser, you can configure babel-preset-env to only include the polyfills and transforms necessary for a particular version:
```json
{
"presets":[
["@babel/env",{
"targets":{
"node":"6.10"
}
}]
]
}
```
For convenience, you can use `"node": "current"` to only include the necessary polyfills and transforms for the Node.js version that you use to run Babel:
```json
{
"presets":[
["@babel/env",{
"targets":{
"node":"current"
}
}]
]
}
```
- [How it Works](#how-it-works)
- [Install](#install)
- [Usage](#usage)
- [Options](#options)
- [Examples](#examples)
- [Issues](#issues)
## How it Works
### Determine environment support for ECMAScript features
Use external data such as [`compat-table`](https://github.com/kangax/compat-table) to determine browser support. (We should create PRs there when necessary)
We can periodically run [build-data.js](https://github.com/babel/babel-preset-env/blob/master/scripts/build-data.js) which generates [plugins.json](https://github.com/babel/babel-preset-env/blob/master/data/plugins.json).
### Maintain a mapping between JavaScript features and Babel plugins
> Currently located at [plugin-features.js](https://github.com/babel/babel-preset-env/blob/master/data/plugin-features.js).
This should be straightforward to do in most cases. There might be cases where plugins should be split up more or certain plugins aren't standalone enough (or impossible to do).
### Support all plugins in Babel that are considered `latest`
> Default behavior without options is the same as `@babel/preset-latest`.
It won't include `stage-x` plugins. env will support all plugins in what we consider the latest version of JavaScript (by matching what we do in [`@babel/preset-latest`](http://babeljs.io/docs/plugins/preset-latest/)).
[Browserslist](https://github.com/ai/browserslist) is a library used to share a supported list of browsers between different front-end tools like [autoprefixer](https://github.com/postcss/autoprefixer), [stylelint](https://stylelint.io/), [eslint-plugin-compat](https://github.com/amilajack/eslint-plugin-compat) and many others.
By default, @babel/preset-env will use [browserslist config sources](https://github.com/ai/browserslist#queries).
For example, to enable only the polyfills and plugins needed for a project targeting *last 2 versions* and *IE10*:
**.babelrc**
```json
{
"presets":[
["@babel/env",{
"useBuiltIns":"entry"
}]
]
}
```
**browserslist**
```
Last 2 versions
IE 10
```
or
**package.json**
```
"browserslist": "last 2 versions, ie 10"
```
Browserslist config will be ignored if: 1) `targets.browsers` was specified 2) or with `ignoreBrowserslistConfig: true` option ([see more](#ignoreBrowserslistConfig)):
#### Targets merging.
1. If [targets.browsers](#targetsbrowsers) is defined - the browserslist config will be ignored. The browsers specified in `targets` will be merged with [any other explicitly defined targets](#targets). If merged, targets defined explicitly will override the same targets received from `targets.browsers`.
2. If [targets.browsers](#targetsbrowsers) is _not_ defined - the program will search browserslist file or `package.json` with `browserslist` field. The search will start from the working directory of the process or from the path specified by the `configPath` option, and go up to the system root. If both a browserslist file and configuration inside a `package.json` are found, an exception will be thrown.
3. If a browserslist config was found and other targets are defined (but not [targets.browsers](#targetsbrowsers)), the targets will be merged in the same way as `targets` defined explicitly with `targets.browsers`.
## Install
With [npm](https://www.npmjs.com):
```sh
npm install --save-dev @babel/preset-env
```
Or [yarn](https://yarnpkg.com):
```sh
yarn add @babel/preset-env --dev
```
## Usage
The default behavior without options runs all transforms (behaves the same as [@babel/preset-latest](https://babeljs.io/docs/plugins/preset-latest/)).
```json
{
"presets":["@babel/env"]
}
```
## Options
For more information on setting options for a preset, refer to the [plugin/preset options](http://babeljs.io/docs/plugins/#plugin-preset-options) documentation.
### `targets`
`{ [string]: number | string }`, defaults to `{}`.
Takes an object of environment versions to support.
Each target environment takes a number or a string (we recommend using a string when specifying minor versions like `node: "6.10"`).
The [data](https://github.com/babel/babel-preset-env/blob/master/data/plugins.json) for this is generated by running the [build-data script](https://github.com/babel/babel-preset-env/blob/master/scripts/build-data.js) which pulls in data from [compat-table](https://kangax.github.io/compat-table).
### `targets.node`
`number | string | "current" | true`
If you want to compile against the current node version, you can specify `"node": true` or `"node": "current"`, which would be the same as `"node": process.versions.node`.
### `targets.browsers`
`Array<string> | string`
A query to select browsers (ex: last 2 versions, > 5%) using [browserslist](https://github.com/ai/browserslist).
Note, browsers' results are overridden by explicit items from `targets`.
### `spec`
`boolean`, defaults to `false`.
Enable more spec compliant, but potentially slower, transformations for any plugins in this preset that support them.
### `loose`
`boolean`, defaults to `false`.
Enable "loose" transformations for any plugins in this preset that allow them.
Enable transformation of ES6 module syntax to another module type.
Setting this to `false` will not transform modules.
### `debug`
`boolean`, defaults to `false`.
Outputs the targets/plugins used and the version specified in [plugin data version](https://github.com/babel/babel-preset-env/blob/master/data/plugins.json) to `console.log`.
### `include`
`Array<string>`, defaults to `[]`.
An array of plugins to always include.
Valid options include any:
- [Babel plugins](https://github.com/babel/babel-preset-env/blob/master/data/plugin-features.js) - both with (`@babel/plugin-transform-spread`) and without prefix (`transform-spread`) are supported.
- [Built-ins](https://github.com/babel/babel-preset-env/blob/master/data/built-in-features.js), such as `map`, `set`, or `object.assign`.
This option is useful if there is a bug in a native implementation, or a combination of a non-supported feature + a supported one doesn't work.
For example, Node 4 supports native classes but not spread. If `super` is used with a spread argument, then the `transform-classes` transform needs to be `include`d, as it is not possible to transpile a spread with `super` otherwise.
> NOTE: The `include` and `exclude` options _only_ work with the [plugins included with this preset](https://github.com/babel/babel-preset-env/blob/master/data/plugin-features.js); so, for example, including `proposal-do-expressions` or excluding `proposal-function-bind` will throw errors. To use a plugin _not_ included with this preset, add them to your [config](https://babeljs.io/docs/usage/babelrc/) directly.
### `exclude`
`Array<string>`, defaults to `[]`.
An array of plugins to always exclude/remove.
The possible options are the same as the `include` option.
This option is useful for "blacklisting" a transform like `transform-regenerator` if you don't use generators and don't want to include `regeneratorRuntime` (when using `useBuiltIns`) or for using another plugin like [fast-async](https://github.com/MatAtBread/fast-async) instead of [Babel's async-to-gen](http://babeljs.io/docs/plugins/proposal-async-generator-functions/).
### `useBuiltIns`
`"usage"` | `"entry"` | `false`, defaults to `false`.
A way to apply `@babel/preset-env` for polyfills (via `@babel/polyfill`).
```sh
npm install @babel/polyfill --save
```
#### `useBuiltIns: 'usage'`
Adds specific imports for polyfills when they are used in each file. We take advantage of the fact that a bundler will load the same polyfill only once.
> NOTE: Only use `require("@babel/polyfill");` once in your whole app.
> Multiple imports or requires of `@babel/polyfill` will throw an error since it can cause global collisions and other issues that are hard to trace.
> We recommend creating a single entry file that only contains the `require` statement.
This option enables a new plugin that replaces the statement `import "@babel/polyfill"` or `require("@babel/polyfill")` with individual requires for `@babel/polyfill` based on environment.
Don't add polyfills automatically per file, or transform `import "@babel/polyfill"` to individual polyfills.
### `forceAllTransforms`
`boolean`, defaults to `false`.
<p><details>
<summary><b>Example</b></summary>
With Babel 7's .babelrc.js support, you can force all transforms to be run if env is set to `production`.
```js
module.exports = {
presets: [
["@babel/env", {
targets: {
chrome: 59,
edge: 13,
firefox: 50,
},
// for uglifyjs...
forceAllTransforms: process.env === "production"
}],
],
};
```
</details></p>
> NOTE: `targets.uglify` is deprecated and will be removed in the next major in
favor of this.
By default, this preset will run all the transforms needed for the targeted
environment(s). Enable this option if you want to force running _all_
transforms, which is useful if the output will be run through UglifyJS or an
environment that only supports ES5.
> NOTE: Uglify has a work-in-progress "Harmony" branch to address the lack of
ES6 support, but it is not yet stable. You can follow its progress in
[UglifyJS2 issue #448](https://github.com/mishoo/UglifyJS2/issues/448). If you
require an alternative minifier which _does_ support ES6 syntax, we recommend
using [babel-minify](https://github.com/babel/minify).
### `configPath`
`string`, defaults to `process.cwd()`
The starting point where the config search for browserslist will start, and ascend to the system root until found.
### `ignoreBrowserslistConfig`
`boolean`, defaults to `false`
Toggles whether or not [browserslist config sources](https://github.com/ai/browserslist#queries) are used, which includes searching for any browserslist files or referencing the browserslist key inside package.json. This is useful for projects that use a browserslist config for files that won't be compiled with Babel.
### `shippedProposals`
`boolean`, defaults to `false`
Toggles enabling support for builtin/feature proposals that have shipped in browsers. If your target environments have native support for a feature proposal, its matching parser syntax plugin is enabled instead of performing any transform. Note that this _does not_ enable the same transformations as [`@babel/preset-stage3`](https://babeljs.io/docs/plugins/preset-stage-3/), since proposals can continue to change before landing in browsers.
If you get a `SyntaxError: Unexpected token ...` error when using the [object-rest-spread](https://github.com/babel/babel/tree/master/packages/babel-plugin-proposal-object-rest-spread) transform then make sure the plugin has been updated to, at least, `v6.19.0`.
Some files were not shown because too many files have changed in this diff
Show More
Reference in New Issue
Block a user
Blocking a user prevents them from interacting with repositories, such as opening or commenting on pull requests or issues. Learn more about blocking a user.
