Babel 6 regeneratorRuntime is not defined

Question

I\'m trying to use async, await from scratch on Babel 6, but I\'m getting regeneratorRuntime is not defined.

.babelrc file

{
    \"presets\": [ \"es2         


        

Answer 1

I fixed this error by installing babel-polyfill

npm install babel-polyfill --save

then I imported it in my app entry point

import http from 'http';
import config from 'dotenv';
import 'babel-polyfill';
import { register } from 'babel-core';
import app from '../app';

for testing I included --require babel-polyfill in my test script

"test": "export NODE_ENV=test|| SET NODE_ENV=test&& mocha --compilers 
  js:babel-core/register --require babel-polyfill server/test/**.js --exit"

Answer 2

For people looking to use the babel-polyfill version 7^ do this with webpack ver3^.

Npm install the module npm i -D @babel/polyfill

Then in your webpack file in your entry point do this

entry: ['@babel/polyfill', path.resolve(APP_DIR, 'App.js')],

Answer 3

I had a setup
with webpack using presets: ['es2015', 'stage-0']
and mocha that was running tests compiled by webpack.

To make my async/await in tests work all I had to do is use mocha with the --require babel-polyfill option:

mocha --require babel-polyfill

Answer 4

To babel7 users and ParcelJS >= 1.10.0 users

npm i @babel/runtime-corejs2
npm i --save-dev @babel/plugin-transform-runtime @babel/core

.babelrc

{
  "plugins": [
    ["@babel/plugin-transform-runtime", {
      "corejs": 2
    }]
  ]
}

taken from https://github.com/parcel-bundler/parcel/issues/1762

Answer 5

If you using Gulp + Babel for a frontend you need to use babel-polyfill

npm install babel-polyfill

and then add a script tag to index.html above all other script tags and reference babel-polyfill from node_modules

Answer 6

You're getting an error because async/await use generators, which are an ES2016 feature, not ES2015. One way to fix this is to install the babel preset for ES2016 (npm install --save babel-preset-es2016) and compile to ES2016 instead of ES2015:

"presets": [
  "es2016",
  // etc...
]

As the other answers mention, you can also use polyfills (though make sure you load the polyfill first before any other code runs). Alternatively, if you don't want to include all of the polyfill dependencies, you can use the babel-regenerator-runtime or the babel-plugin-transform-runtime.