Babel 6 Regeneratorruntime Is Not Defined

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

package.json

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

.babelrc

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

.js with async/await (sample code)

"use strict";

export default async function foo() {
  var s = await bar();
  console.log(s);
}

function bar() {
  return "bar";
}

In the startup file

require("babel-core/register");
require("babel-polyfill");

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

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

package.json

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

.babelrc

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

.js with async/await (sample code)

"use strict";

export default async function foo() {
  var s = await bar();
  console.log(s);
}

function bar() {
  return "bar";
}

In the startup file

require("babel-core/register");
require("babel-polyfill");

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

Babel 7 - ReferenceError: regeneratorRuntime is not defined

Updated Answer:

If you are using Babel 7.4.0 or newer, then @babel/polyfill has been deprecated. Instead, you will want to use the following at the top of your main js file (likely index.js or similar):

import "core-js/stable";
import "regenerator-runtime/runtime";

Install these packages either with npm:

npm install --save core-js
npm install --save regenerator-runtime    

or with yarn:

yarn add core-js
yarn add regenerator-runtime

Original Answer:

I just encountered this problem and came across the following solution:

In package.json I had @babel/polyfill as a dependency. However, in my index.js (My main js file) I had neglected to place the following line at the the top:

import '@babel/polyfill'

Once I imported it, everything worked fine.

I did not need to install babel-runtime as other answers are suggesting.

Uncaught ReferenceError: regeneratorRuntime is not defined in react 17, webpack 5 while making api calls through actions

For Babel 7, install these two dependencies:

npm install --save @babel/runtime 
npm install --save-dev @babel/plugin-transform-runtime

And, in .babelrc, add:

{
    "presets": ["@babel/preset-env"],
    "plugins": [
        ["@babel/plugin-transform-runtime"]
    ]
}

regeneratorRuntime is not defined Gulp + Webpack + Babel

So, after 2 days of searching and testing I finally resolved this issue:
1. Clean webpack works perfectly with recommended config:

package.json

{
  "name": "babel-test",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
    "webpack": "webpack --config webpack.config.js --color"
  },
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "@babel/core": "^7.10.2",
    "@babel/plugin-transform-runtime": "^7.10.1",
    "@babel/preset-env": "^7.10.2",
    "babel-loader": "^8.1.0",
    "webpack": "^4.43.0",
    "webpack-cli": "^3.3.11"
  }
}

webpack.config.js

const path = require('path');
module.exports = {
    mode: 'development',
    entry: {
        index: './index.js'
    },
    output: {
        path: path.resolve(__dirname, 'public'),
        filename: 'bundle.js',
    },
    module: {
        rules: [
            {
                test: /\.m?js$/,
                exclude: /(node_modules|bower_components)/,
                use: {
                    loader: 'babel-loader',
                    options: {
                        presets: ['@babel/preset-env'],
                        plugins: [
                            ["@babel/plugin-transform-runtime", { "regenerator": true }
                            ]
                        ]
                    }
                }
            }
        ]
    }
}

1. I updated all webpack and babel related packages to the latest stable versions.

2. There was a problem in my gulp file. So I changed usage of webpack through webpack-stream. Before:

   const webpack = require('webpack');
    gulp.task('scripts', function (callback) {
      webpack(require('./webpack.config.js'), function (err, stats) {
        if (err) {
          console.log(err.toString());
        }    
        console.log(stats.toString());
        callback();
      });
    });

After:

 const webpack = require('webpack-stream');
 gulp.task('scripts', function() {
   return gulp.src(settings.themeLocation + "js/scripts.js")
     .pipe(webpack( require('./webpack.config.js') ))
     .pipe(gulp.dest(settings.themeLocation + "js"));
 });

after rollup build: regeneratorRuntime is not defined

It's been almost 2 years since I last used rollup. Anyway in a project I found (where we faced the same issues), I saw the following plugins order:

plugins: [
 [
    '@babel/plugin-transform-runtime',
 ],           
 ["@babel/plugin-proposal-optional-chaining"],
 ["@babel/plugin-proposal-nullish-coalescing-operator"],
 ["babel-plugin-transform-for-of-without-iterator"],
]

The @babel/plugin-transform-runtime does the magic.

npm i @babel/plugin-transform-runtime

To install

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