karma-babel-polyfill

0.0.5 verified Sat Apr 25 auth: no javascript deprecated

A Karma plugin that injects babel-polyfill into the test browser environment, ensuring that ES2015+ APIs (e.g., Promise, Map, Set) are available when running tests with Karma. Version 0.0.5 is the final release; the package has not been updated since 2016 and is considered deprecated in favor of using @babel/polyfill or @babel/regenerator directly with Karma's configuration. It requires karma as a peer dependency and is designed for use with older Babel 6 setups.

Common errors

error Error: Cannot find module 'karma-babel-polyfill' ↓

cause Package not installed or not listed in plugins array in karma.conf.js.

fix

Run: npm install --save-dev karma-babel-polyfill Then add 'karma-babel-polyfill' to the plugins array in karma.conf.js.

error TypeError: babelPolyfill is not a function ↓

cause Incorrect usage of the module via import or require in wrong context.

fix

Do not manually call require('karma-babel-polyfill') in config; instead use the string 'babel-polyfill' in the frameworks array.

error ReferenceError: regeneratorRuntime is not defined ↓

cause babel-polyfill may not be loaded before test files; also may need add regenerator runtime.

fix

Ensure 'babel-polyfill' is in frameworks array. If using async/await, consider using @babel/plugin-transform-runtime.

Warnings

deprecated Package has not been updated since 2016 and relies on deprecated babel-polyfill which is no longer maintained. ↓

fix Migrate to using @babel/polyfill or @babel/regenerator with Karma's single-run mode, or use core-js directly.

gotcha Frameworks entry must be 'babel-polyfill' not 'karma-babel-polyfill' ↓

fix In karma.conf.js, set frameworks: ['babel-polyfill']

gotcha The package only provides CommonJS module; cannot be imported via ES import. ↓

fix Use require() or list in karma.conf.js as string.

breaking Only works with Babel 6; not compatible with Babel 7 or @babel/core. ↓

fix Update to @babel/polyfill and corresponding Karma plugins.

Install

npm install karma-babel-polyfill

yarn add karma-babel-polyfill

pnpm add karma-babel-polyfill

Imports

default

wrong

import karmaBabelPolyfill from 'karma-babel-polyfill';

correct

module.exports = require('karma-babel-polyfill');

This package is CommonJS-only and does not provide an ESM export.

frameworks
wrong
```
frameworks: ['karma-babel-polyfill']
```
correct
```
frameworks: ['babel-polyfill']
```
In karma.conf.js, add the string 'babel-polyfill' to the frameworks array; do not use the package name.
plugins
wrong
```
plugins: [require('karma-babel-polyfill')]
```
correct
```
plugins: ['karma-babel-polyfill']
```
Alternatively, the package can be listed in the plugins array if not auto-loaded.

Quickstart

Configures Karma to use babel-polyfill so that ES2015 features are available in test browsers.

// karma.conf.js
module.exports = function(config) {
  config.set({
    frameworks: ['mocha', 'babel-polyfill'], // Add 'babel-polyfill'
    files: ['test/**/*.js'],
    preprocessors: {
      'test/**/*.js': ['babel']
    },
    babelPreprocessor: {
      options: {
        presets: ['env']
      }
    },
    plugins: ['karma-babel-polyfill', 'karma-mocha', 'karma-chrome-launcher', 'karma-babel-preprocessor'],
    browsers: ['ChromeHeadless'],
    singleRun: true
  });
};

// Install: npm install --save-dev karma-babel-polyfill karma karma-mocha karma-chrome-launcher karma-babel-preprocessor babel-preset-env