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Turn async generator functions into ES2015 generators

Package Exports

  • @babel/plugin-proposal-async-generator-functions

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (@babel/plugin-proposal-async-generator-functions) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

@babel/plugin-proposal-async-generator-functions

Turn async generator functions and for-await statements to ES2015 generators

Example

In

async function* agf() {
  await 1;
  yield 2;
}

Out

var _asyncGenerator = ...

let agf = (() => {
  var _ref = _asyncGenerator.wrap(function* () {
    yield _asyncGenerator.await(1);
    yield 2;
  });

  return function agf() {
    return _ref.apply(this, arguments);
  };
})();

For await example

async function f() {
  for await (let x of y) {
    g(x);
  }
}

Example Usage

async function* genAnswers() {
  var stream = [ Promise.resolve(4), Promise.resolve(9), Promise.resolve(12) ];
  var total = 0;
  for await (let val of stream) {
    total += await val;
    yield total;
  }
}

function forEach(ai, fn) {
  return ai.next().then(function (r) {
    if (!r.done) {
      fn(r);
      return forEach(ai, fn);
    }
  });
}

var output = 0;
forEach(genAnswers(), function(val) { output += val.value })
.then(function () {
  console.log(output); // 42
});

Try it Out in the REPL

Installation

npm install --save-dev @babel/plugin-proposal-async-generator-functions

Usage

.babelrc

{
  "plugins": ["@babel/plugin-proposal-async-generator-functions"]
}

Via CLI

babel --plugins @babel/plugin-proposal-async-generator-functions script.js

Via Node API

require("@babel/core").transform("code", {
  plugins: ["@babel/plugin-proposal-async-generator-functions"]
});

References