3746273eda
* Path#ensureBlock keeps path context
This ensures that if you're inside an ArrowFunction with an expression body (say, you're on the BooleanLiteral in `() => true`), you don't suddenly lose your path context after inserting a variable.
This is because of 82d8aded8e (diff-9e0668ad44535be897b934e7077ecea5R14). Basically, an innocent `Scope#push` caused my visitor to suddenly stop working. Now, we mutate the Path so it's still in the tree.
* Tests
Woah, what's going on here?
A monorepo, muhahahahahaha. See the monorepo design doc for reasoning.
Core Packages
| Package | Version | Dependencies |
|---|---|---|
babel-core |
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babylon |
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babel-traverse |
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babel-generator |
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babel-core is the Babel compiler itself; it exposes the babel.transform method, where transformedCode = transform(src).code.
The compiler can be broken down into 3 parts:
- The parser:
babylon(moved to a separate repo and versioned independently) - The transformer[s]: All the plugins/presets
- These all use
babel-traverseto traverse through the AST
- These all use
- The generator:
babel-generator
The flow goes like this:
input string -> babylon parser -> AST -> transformer[s] -> AST -> babel-generator -> output string
Check out the babel-handbook for more information on this.
Other
| Package | Version | Dependencies |
|---|---|---|
babel-cli |
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babel-types |
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babel-polyfill |
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babel-runtime |
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babel-register |
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babel-template |
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babel-helpers |
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babel-code-frame |
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babel-cliis the CLI tool that runsbabel-coreand helps with outputting to a directory, a file, stdout and more (also includesbabel-node). Check out the docs.babel-typesis used to validate, build and change AST nodes.babel-polyfillis literally a wrapper aroundcore-jsand regenerator-runtime. Check out the docs.babel-runtimeis similar to the polyfill except that it doesn't modify the global scope and is to be used withbabel-plugin-transform-runtime(usually in library/plugin code). Check out the docs.babel-registeris a way to automatically compile files with Babel on the fly by binding to Node.jsrequire. Check out the docs.babel-templateis a helper function that allows constructing AST nodes from a string presentation of the code; this eliminates the tedium of usingbabel-typesfor building AST nodes.babel-helpersis a set of pre-madebabel-templatefunctions that are used in some Babel plugins.babel-code-frameis a standalone package used to generate errors that print the source code and point to error locations.
Presets
After Babel 6, the default transforms were removed; if you don't specify any plugins/presets, Babel will just return the original source code.
The transformer[s] used in Babel are the independent pieces of code that transform specific things. For example: the es2015-arrow-functions transform specifically changes arrow functions into regular functions. A preset is simply an array of plugins that make it easier to run a whole a set of transforms without specifying each one manually.
| Package | Version | Dependencies | Description |
|---|---|---|---|
babel-preset-env |
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automatically determines plugins and polyfills you need based on your supported environments |
You can find community maintained presets on npm
Plugins
Plugins are the heart of Babel and what make it work.
You can find community plugins on npm.
Transform Plugins
There are many kinds of plugins: ones that convert ES6/ES2015 to ES5, transform to ES3, minification, JSX, flow, experimental features, and more. Check out our website for more.
Syntax Plugins
These just enable the transform plugins to be able to parse certain features (the transform plugins already include the syntax plugins so you don't need both): babel-plugin-syntax-x. Check out our website for more.
Helpers
These are mostly for internal use in various plugins: babel-helper-x.