Function sent (#5920)

* Create "babel-helper-wrap-function"

It contains the logic to wrap a function inside a call expression.
It was part of the "babel-helper-remap-async-to-generator" package, but
it is needed to transpile "function.sent"

* Create "babel-transform-function-sent"

It transforms the "function.sent" meta property by replacing it with
"yield" and making the generator ignore the first ".next()" call.

* "function.sent" is the last value passed to .next(), not the first one

* Disable exec tests on old node

* Fix flow error

* Add "transform-function-sent" to "stage-2" preset

* Do every trasformation in one traversal

* Test for "yield function.sent"

* [skip ci]

* Fix some typos [skip ci]
This commit is contained in:
Nicolò Ribaudo 2017-07-25 17:07:01 +02:00 committed by Henry Zhu
parent 4a35243118
commit fb9a752262
47 changed files with 603 additions and 145 deletions

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@ -6,7 +6,7 @@
"license": "MIT", "license": "MIT",
"main": "lib/index.js", "main": "lib/index.js",
"dependencies": { "dependencies": {
"babel-helper-function-name": "7.0.0-alpha.15", "babel-helper-wrap-function": "7.0.0-alpha.15",
"babel-template": "7.0.0-alpha.15", "babel-template": "7.0.0-alpha.15",
"babel-traverse": "7.0.0-alpha.15", "babel-traverse": "7.0.0-alpha.15",
"babel-types": "7.0.0-alpha.15" "babel-types": "7.0.0-alpha.15"

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@ -1,30 +1,10 @@
/* @noflow */ /* @noflow */
import type { NodePath } from "babel-traverse"; import type { NodePath } from "babel-traverse";
import nameFunction from "babel-helper-function-name"; import wrapFunction from "babel-helper-wrap-function";
import template from "babel-template";
import * as t from "babel-types"; import * as t from "babel-types";
import rewriteForAwait from "./for-await"; import rewriteForAwait from "./for-await";
const buildWrapper = template(`
(() => {
var REF = FUNCTION;
return function NAME(PARAMS) {
return REF.apply(this, arguments);
};
})
`);
const namedBuildWrapper = template(`
(() => {
var REF = FUNCTION;
function NAME(PARAMS) {
return REF.apply(this, arguments);
}
return NAME;
})
`);
const awaitVisitor = { const awaitVisitor = {
Function(path) { Function(path) {
path.skip(); path.skip();
@ -71,123 +51,6 @@ const awaitVisitor = {
}, },
}; };
function classOrObjectMethod(path: NodePath, callId: Object) {
const node = path.node;
const body = node.body;
node.async = false;
const container = t.functionExpression(
null,
[],
t.blockStatement(body.body),
true,
);
body.body = [
t.returnStatement(
t.callExpression(t.callExpression(callId, [container]), []),
),
];
// Regardless of whether or not the wrapped function is a an async method
// or generator the outer function should not be
node.generator = false;
// Unwrap the wrapper IIFE's environment so super and this and such still work.
path
.get("body.body.0.argument.callee.arguments.0")
.unwrapFunctionEnvironment();
}
function plainFunction(path: NodePath, callId: Object) {
const node = path.node;
const isDeclaration = path.isFunctionDeclaration();
const asyncFnId = node.id;
let wrapper = buildWrapper;
if (path.isArrowFunctionExpression()) {
path.arrowFunctionToExpression();
} else if (!isDeclaration && asyncFnId) {
wrapper = namedBuildWrapper;
}
node.async = false;
node.generator = true;
node.id = null;
if (isDeclaration) {
node.type = "FunctionExpression";
}
const built = t.callExpression(callId, [node]);
const container = wrapper({
NAME: asyncFnId || null,
REF: path.scope.generateUidIdentifier("ref"),
FUNCTION: built,
PARAMS: node.params.reduce(
(acc, param) => {
acc.done =
acc.done || t.isAssignmentPattern(param) || t.isRestElement(param);
if (!acc.done) {
acc.params.push(path.scope.generateUidIdentifier("x"));
}
return acc;
},
{
params: [],
done: false,
},
).params,
}).expression;
if (isDeclaration) {
const declar = t.variableDeclaration("let", [
t.variableDeclarator(
t.identifier(asyncFnId.name),
t.callExpression(container, []),
),
]);
declar._blockHoist = true;
if (path.parentPath.isExportDefaultDeclaration()) {
// change the path type so that replaceWith() does not wrap
// the identifier into an expressionStatement
path.parentPath.insertBefore(declar);
path.parentPath.replaceWith(
t.exportNamedDeclaration(null, [
t.exportSpecifier(
t.identifier(asyncFnId.name),
t.identifier("default"),
),
]),
);
return;
}
path.replaceWith(declar);
} else {
const retFunction = container.body.body[1].argument;
if (!asyncFnId) {
nameFunction({
node: retFunction,
parent: path.parent,
scope: path.scope,
});
}
if (!retFunction || retFunction.id || node.params.length) {
// we have an inferred function id or params so we need this wrapper
path.replaceWith(t.callExpression(container, []));
} else {
// we can omit this wrapper as the conditions it protects for do not apply
path.replaceWith(built);
}
}
}
export default function(path: NodePath, file: Object, helpers: Object) { export default function(path: NodePath, file: Object, helpers: Object) {
if (!helpers) { if (!helpers) {
// bc for 6.15 and earlier // bc for 6.15 and earlier
@ -199,9 +62,8 @@ export default function(path: NodePath, file: Object, helpers: Object) {
wrapAwait: helpers.wrapAwait, wrapAwait: helpers.wrapAwait,
}); });
if (path.isClassMethod() || path.isObjectMethod()) { path.node.async = false;
classOrObjectMethod(path, helpers.wrapAsync); path.node.generator = true;
} else {
plainFunction(path, helpers.wrapAsync); wrapFunction(path, helpers.wrapAsync);
}
} }

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@ -0,0 +1,3 @@
src
test
*.log

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@ -0,0 +1,27 @@
# babel-helper-wrap-function
This helper wraps a function within a call expression. It works with any function: statements, expressions and methods; both named and anonymous.
## Example
**In**
```js
(function () {
}());
```
**Out**
```js
_wrapper(function () {
})();
```
## Usage
```js
import wrapFunction from "babel-helper-wrap-function";
wrapFunction(nodePathOfTheFunction, nodeWhichReferencesToTheWrapper);
```

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@ -0,0 +1,14 @@
{
"name": "babel-helper-wrap-function",
"version": "7.0.0-alpha.15",
"description": "Helper to wrap functions inside a function call.",
"repository": "https://github.com/babel/babel/tree/master/packages/babel-helper-wrap-function",
"license": "MIT",
"main": "lib/index.js",
"dependencies": {
"babel-helper-function-name": "7.0.0-alpha.15",
"babel-template": "7.0.0-alpha.15",
"babel-traverse": "7.0.0-alpha.15",
"babel-types": "7.0.0-alpha.15"
}
}

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@ -0,0 +1,146 @@
/* @flow */
import type { NodePath } from "babel-traverse";
import nameFunction from "babel-helper-function-name";
import template from "babel-template";
import * as t from "babel-types";
const buildWrapper = template(`
(() => {
var REF = FUNCTION;
return function NAME(PARAMS) {
return REF.apply(this, arguments);
};
})
`);
const namedBuildWrapper = template(`
(() => {
var REF = FUNCTION;
function NAME(PARAMS) {
return REF.apply(this, arguments);
}
return NAME;
})
`);
function classOrObjectMethod(path: NodePath, callId: Object) {
const node = path.node;
const body = node.body;
const container = t.functionExpression(
null,
[],
t.blockStatement(body.body),
true,
);
body.body = [
t.returnStatement(
t.callExpression(t.callExpression(callId, [container]), []),
),
];
// Regardless of whether or not the wrapped function is a an async method
// or generator the outer function should not be
node.async = false;
node.generator = false;
// Unwrap the wrapper IIFE's environment so super and this and such still work.
path
.get("body.body.0.argument.callee.arguments.0")
.unwrapFunctionEnvironment();
}
function plainFunction(path: NodePath, callId: Object) {
const node = path.node;
const isDeclaration = path.isFunctionDeclaration();
const functionId = node.id;
let wrapper = buildWrapper;
if (path.isArrowFunctionExpression()) {
path.arrowFunctionToExpression();
} else if (!isDeclaration && functionId) {
wrapper = namedBuildWrapper;
}
node.id = null;
if (isDeclaration) {
node.type = "FunctionExpression";
}
const built = t.callExpression(callId, [node]);
const container = wrapper({
NAME: functionId || null,
REF: path.scope.generateUidIdentifier("ref"),
FUNCTION: built,
PARAMS: node.params.reduce(
(acc, param) => {
acc.done =
acc.done || t.isAssignmentPattern(param) || t.isRestElement(param);
if (!acc.done) {
acc.params.push(path.scope.generateUidIdentifier("x"));
}
return acc;
},
{
params: [],
done: false,
},
).params,
}).expression;
if (isDeclaration && functionId) {
const declar = t.variableDeclaration("let", [
t.variableDeclarator(
t.identifier(functionId.name),
t.callExpression(container, []),
),
]);
(declar: any)._blockHoist = true;
if (path.parentPath.isExportDefaultDeclaration()) {
// change the path type so that replaceWith() does not wrap
// the identifier into an expressionStatement
path.parentPath.insertBefore(declar);
path.parentPath.replaceWith(
t.exportNamedDeclaration(null, [
t.exportSpecifier(
t.identifier(functionId.name),
t.identifier("default"),
),
]),
);
return;
}
path.replaceWith(declar);
} else {
const retFunction = container.body.body[1].argument;
if (!functionId) {
nameFunction({
node: retFunction,
parent: path.parent,
scope: path.scope,
});
}
if (!retFunction || retFunction.id || node.params.length) {
// we have an inferred function id or params so we need this wrapper
path.replaceWith(t.callExpression(container, []));
} else {
// we can omit this wrapper as the conditions it protects for do not apply
path.replaceWith(built);
}
}
}
export default function wrapFunction(path: NodePath, callId: Object) {
if (path.isClassMethod() || path.isObjectMethod()) {
classOrObjectMethod(path, callId);
} else {
plainFunction(path, callId);
}
}

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@ -611,6 +611,16 @@ helpers.toConsumableArray = template(`
}); });
`); `);
helpers.skipFirstGeneratorNext = template(`
(function (fn) {
return function () {
var it = fn.apply(this, arguments);
it.next();
return it;
}
});
`);
helpers.toPropertyKey = template(` helpers.toPropertyKey = template(`
(function (key) { (function (key) {
if (typeof key === "symbol") { if (typeof key === "symbol") {

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@ -0,0 +1,3 @@
src
test
*.log

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@ -0,0 +1,66 @@
# babel-plugin-transform-function-sent
> Compile the `function.sent` meta property, used inside generator functions, to valid ES2015 code.
## Example
```js
function* generator() {
console.log("Sent", function.sent);
console.log("Yield", yield);
}
const iterator = generator();
iterator.next(1); // Logs "Sent 1"
iterator.next(2); // Logs "Yield 2"
```
Is compiled roughly to
```js
let generator = _skipFirstGeneratorNext(function* () {
const _functionSent = yield;
console.log("Sent", _functionSent);
console.log("Yield", yield);
});
const iterator = generator();
iterator.next(1); // Logs "Sent 1"
iterator.next(2); // Logs "Yield 1"
```
## Installation
```sh
npm install --save-dev babel-plugin-transform-function-sent
```
## Usage
### Via `.babelrc` (Recommended)
**.babelrc**
```json
{
"plugins": ["transform-function-sent"]
}
```
### Via CLI
```sh
babel --plugins transform-function-sent script.js
```
### Via Node API
```javascript
require("babel-core").transform("code", {
plugins: ["transform-function-sent"]
});
```
## References
* [Proposal](https://github.com/allenwb/ESideas/blob/master/Generator%20metaproperty.md)

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@ -0,0 +1,18 @@
{
"name": "babel-plugin-transform-function-sent",
"version": "7.0.0-alpha.15",
"description": "Compile the function.sent meta propety to valid ES2015 code",
"repository": "https://github.com/babel/babel/tree/master/packages/babel-plugin-transform-function-sent",
"license": "MIT",
"main": "lib/index.js",
"keywords": [
"babel-plugin"
],
"dependencies": {
"babel-plugin-syntax-function-sent": "7.0.0-alpha.15",
"babel-helper-wrap-function": "7.0.0-alpha.15"
},
"devDependencies": {
"babel-helper-plugin-test-runner": "7.0.0-alpha.15"
}
}

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@ -0,0 +1,56 @@
import syntaxFunctionSent from "babel-plugin-syntax-function-sent";
import wrapFunction from "babel-helper-wrap-function";
export default function({ types: t }) {
const isFunctionSent = node =>
t.isIdentifier(node.meta, { name: "function" }) &&
t.isIdentifier(node.property, { name: "sent" });
const yieldVisitor = {
Function(path) {
path.skip();
},
YieldExpression(path) {
const replaced = t.isAssignmentExpression(path.parent, {
left: this.sentId,
});
if (!replaced) {
path.replaceWith(t.assignmentExpression("=", this.sentId, path.node));
}
},
MetaProperty(path) {
if (isFunctionSent(path.node)) {
path.replaceWith(this.sentId);
}
},
};
return {
inherits: syntaxFunctionSent,
visitor: {
MetaProperty(path, state) {
if (!isFunctionSent(path.node)) return;
const fnPath = path.getFunctionParent();
if (!fnPath.node.generator) {
throw new Error("Parent generator function not found");
}
const sentId = path.scope.generateUidIdentifier("function.sent");
fnPath.traverse(yieldVisitor, { sentId });
fnPath.node.body.body.unshift(
t.variableDeclaration("let", [
t.variableDeclarator(sentId, t.yieldExpression()),
]),
);
wrapFunction(fnPath, state.addHelper("skipFirstGeneratorNext"));
},
},
};
}

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@ -0,0 +1,3 @@
function* gen() {
let sent = function.sent;
}

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@ -0,0 +1,13 @@
let sent, yielded;
function* gen() {
sent = function.sent;
yielded = yield;
}
const it = gen();
it.next(1);
it.next(2);
assert.equal(sent, 1);
assert.equal(yielded, 2);

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@ -0,0 +1,13 @@
let gen = (() => {
var _ref = _skipFirstGeneratorNext(function* () {
let _functionSent = yield;
let sent = _functionSent;
});
return function gen() {
return _ref.apply(this, arguments);
};
})();
function _skipFirstGeneratorNext(fn) { return function () { var it = fn.apply(this, arguments); it.next(); return it; }; }

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@ -0,0 +1,3 @@
{
"minNodeVersion": "6.0.0"
}

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@ -0,0 +1,10 @@
(function* () {
const a = function.sent;
const b = function.sent;
yield 4;
const c = function.sent;
const d = yield;
const e = function.sent;
return [ a, b, c, d, e ];
}());

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@ -0,0 +1,23 @@
const values = [];
function* gen() {
values.push(function.sent);
values.push(function.sent);
values.push(yield "foo");
values.push(function.sent);
values.push(yield);
values.push(function.sent);
values.push(function.sent);
}
const it = gen();
assert.deepEqual(values, []);
assert.equal(it.next(1).value, "foo");
assert.deepEqual(values, [ 1, 1 ]);
assert.equal(it.next(2).value, undefined);
assert.deepEqual(values, [ 1, 1, 2, 2 ]);
assert.equal(it.next(3).done, true);
assert.deepEqual(values, [ 1, 1, 2, 2, 3, 3, 3 ]);

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@ -0,0 +1,13 @@
function _skipFirstGeneratorNext(fn) { return function () { var it = fn.apply(this, arguments); it.next(); return it; }; }
_skipFirstGeneratorNext(function* () {
let _functionSent = yield;
const a = _functionSent;
const b = _functionSent;
_functionSent = yield 4;
const c = _functionSent;
const d = _functionSent = yield;
const e = _functionSent;
return [a, b, c, d, e];
})();

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@ -0,0 +1,3 @@
{
"minNodeVersion": "6.0.0"
}

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@ -0,0 +1,3 @@
{
"plugins": ["transform-function-sent"]
}

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@ -0,0 +1,4 @@
function* foo() {
let a = yield;
return yield;
}

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@ -0,0 +1,4 @@
function* foo() {
let a = yield;
return yield;
}

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@ -0,0 +1,3 @@
(function* () {
yield function.sent;
})();

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@ -0,0 +1,7 @@
function _skipFirstGeneratorNext(fn) { return function () { var it = fn.apply(this, arguments); it.next(); return it; }; }
_skipFirstGeneratorNext(function* () {
let _functionSent = yield;
_functionSent = yield _functionSent;
})();

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@ -0,0 +1,3 @@
async function* foo() {
await function.sent;
}

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@ -0,0 +1,15 @@
var _asyncGenerator = function () { function AwaitValue(value) { this.value = value; } function AsyncGenerator(gen) { var front, back; function send(key, arg) { return new Promise(function (resolve, reject) { var request = { key: key, arg: arg, resolve: resolve, reject: reject, next: null }; if (back) { back = back.next = request; } else { front = back = request; resume(key, arg); } }); } function resume(key, arg) { try { var result = gen[key](arg); var value = result.value; if (value instanceof AwaitValue) { Promise.resolve(value.value).then(function (arg) { resume("next", arg); }, function (arg) { resume("throw", arg); }); } else { settle(result.done ? "return" : "normal", result.value); } } catch (err) { settle("throw", err); } } function settle(type, value) { switch (type) { case "return": front.resolve({ value: value, done: true }); break; case "throw": front.reject(value); break; default: front.resolve({ value: value, done: false }); break; } front = front.next; if (front) { resume(front.key, front.arg); } else { back = null; } } this._invoke = send; if (typeof gen.return !== "function") { this.return = undefined; } } if (typeof Symbol === "function" && Symbol.asyncIterator) { AsyncGenerator.prototype[Symbol.asyncIterator] = function () { return this; }; } AsyncGenerator.prototype.next = function (arg) { return this._invoke("next", arg); }; AsyncGenerator.prototype.throw = function (arg) { return this._invoke("throw", arg); }; AsyncGenerator.prototype.return = function (arg) { return this._invoke("return", arg); }; return { wrap: function (fn) { return function () { return new AsyncGenerator(fn.apply(this, arguments)); }; }, await: function (value) { return new AwaitValue(value); } }; }();
let foo = (() => {
var _ref = _asyncGenerator.wrap(_skipFirstGeneratorNext(function* () {
let _functionSent = yield;
_functionSent = yield _asyncGenerator.await(_functionSent);
}));
return function foo() {
return _ref.apply(this, arguments);
};
})();
function _skipFirstGeneratorNext(fn) { return function () { var it = fn.apply(this, arguments); it.next(); return it; }; }

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@ -0,0 +1,3 @@
{
"plugins": [ "transform-function-sent", "transform-async-generator-functions" ]
}

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@ -0,0 +1,5 @@
class Foo {
*gen() {
return function.sent;
}
}

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@ -0,0 +1,12 @@
function _skipFirstGeneratorNext(fn) { return function () { var it = fn.apply(this, arguments); it.next(); return it; }; }
class Foo {
gen() {
return _skipFirstGeneratorNext(function* () {
let _functionSent = yield;
return _functionSent;
})();
}
}

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@ -0,0 +1,3 @@
export default function* () {
return function.sent;
}

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@ -0,0 +1,7 @@
function _skipFirstGeneratorNext(fn) { return function () { var it = fn.apply(this, arguments); it.next(); return it; }; }
export default _skipFirstGeneratorNext(function* () {
let _functionSent = yield;
return _functionSent;
});

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@ -0,0 +1,3 @@
export default function* gen() {
return function.sent;
}

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@ -0,0 +1,15 @@
let gen = (() => {
var _ref = _skipFirstGeneratorNext(function* () {
let _functionSent = yield;
return _functionSent;
});
return function gen() {
return _ref.apply(this, arguments);
};
})();
function _skipFirstGeneratorNext(fn) { return function () { var it = fn.apply(this, arguments); it.next(); return it; }; }
export { gen as default };

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@ -0,0 +1,3 @@
export function* gen() {
return function.sent;
}

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@ -0,0 +1,13 @@
function _skipFirstGeneratorNext(fn) { return function () { var it = fn.apply(this, arguments); it.next(); return it; }; }
export let gen = (() => {
var _ref = _skipFirstGeneratorNext(function* () {
let _functionSent = yield;
return _functionSent;
});
return function gen() {
return _ref.apply(this, arguments);
};
})();

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@ -0,0 +1,3 @@
(function* () {
return function.sent;
}());

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@ -0,0 +1,7 @@
function _skipFirstGeneratorNext(fn) { return function () { var it = fn.apply(this, arguments); it.next(); return it; }; }
_skipFirstGeneratorNext(function* () {
let _functionSent = yield;
return _functionSent;
})();

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@ -0,0 +1,3 @@
const foo = function* gen() {
return function.sent;
};

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@ -0,0 +1,15 @@
function _skipFirstGeneratorNext(fn) { return function () { var it = fn.apply(this, arguments); it.next(); return it; }; }
const foo = (() => {
var _ref = _skipFirstGeneratorNext(function* () {
let _functionSent = yield;
return _functionSent;
});
function gen() {
return _ref.apply(this, arguments);
}
return gen;
})();

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@ -0,0 +1,5 @@
const obj = {
*gen() {
return function.sent;
},
};

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@ -0,0 +1,12 @@
function _skipFirstGeneratorNext(fn) { return function () { var it = fn.apply(this, arguments); it.next(); return it; }; }
const obj = {
gen() {
return _skipFirstGeneratorNext(function* () {
let _functionSent = yield;
return _functionSent;
})();
}
};

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@ -0,0 +1,3 @@
{
"plugins": ["transform-function-sent"]
}

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@ -0,0 +1,3 @@
function* gen() {
return function.sent;
}

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@ -0,0 +1,13 @@
let gen = (() => {
var _ref = _skipFirstGeneratorNext(function* () {
let _functionSent = yield;
return _functionSent;
});
return function gen() {
return _ref.apply(this, arguments);
};
})();
function _skipFirstGeneratorNext(fn) { return function () { var it = fn.apply(this, arguments); it.next(); return it; }; }

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@ -0,0 +1,3 @@
import runner from "babel-helper-plugin-test-runner";
runner(__dirname);

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@ -9,6 +9,7 @@
"main": "lib/index.js", "main": "lib/index.js",
"dependencies": { "dependencies": {
"babel-plugin-transform-class-properties": "7.0.0-alpha.15", "babel-plugin-transform-class-properties": "7.0.0-alpha.15",
"babel-plugin-transform-function-sent": "7.0.0-alpha.15",
"babel-preset-stage-3": "7.0.0-alpha.15" "babel-preset-stage-3": "7.0.0-alpha.15"
} }
} }

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@ -1,10 +1,11 @@
import presetStage3 from "babel-preset-stage-3"; import presetStage3 from "babel-preset-stage-3";
import transformClassProperties from "babel-plugin-transform-class-properties"; import transformClassProperties from "babel-plugin-transform-class-properties";
import transformFunctionSent from "babel-plugin-transform-function-sent";
export default function() { export default function() {
return { return {
presets: [presetStage3], presets: [presetStage3],
plugins: [transformClassProperties], plugins: [transformClassProperties, transformFunctionSent],
}; };
} }