Babel 6 regeneratorRuntime is not defined

babel-polyfill (deprecated as of Babel 7.4) is required. You must also install it in order to get async/await working.

npm i -D babel-core babel-polyfill babel-preset-es2015 babel-preset-stage-0 babel-loader


"devDependencies": {
  "babel-core": "^6.0.20",
  "babel-polyfill": "^6.0.16",
  "babel-preset-es2015": "^6.0.15",
  "babel-preset-stage-0": "^6.0.15"


  "presets": [ "es2015", "stage-0" ]

.js with async/await (sample code)

"use strict";

export default async function foo() {
  var s = await bar();

function bar() {
  return "bar";

In the startup file


If you are using webpack you need to put it as the first value of your entry array in your webpack configuration file (usually webpack.config.js), as per @Cemen comment:

module.exports = {
  entry: ['babel-polyfill', './test.js'],

  output: {
    filename: 'bundle.js'       

  module: {
    loaders: [
      { test: /\.jsx?$/, loader: 'babel', }

If you want to run tests with babel then use:

mocha --compilers js:babel-core/register --require babel-polyfill

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