karma-systemjs

0.16.0 verified Fri May 01 auth: no javascript maintenance

A Karma plugin adapter for loading test files via SystemJS module loader instead of script tags. Current version 0.16.0 disables SystemJS bundles by default; set useBundles: true to enable. Supports transpilers like Babel and TypeScript. Key differentiator: integrates SystemJS module loading into Karma test runner for testing ES modules with transpilation. Requires manual configuration of SystemJS config file and serving of dependencies. Note: The project appears to be in maintenance mode with limited recent activity.

Common errors

error TypeError: 'undefined' is not a function (evaluating 'Function.prototype.bind') ↓

cause PhantomJS v1.x does not support Function.prototype.bind, required by transpilers.

fix

Add 'phantomjs-polyfill' to your SystemJS config: System.config({ map: { 'phantomjs-polyfill': 'node_modules/phantomjs-polyfill/bind-polyfill.js' } });

error Error: Mismatched anonymous define() module: function (...) { ... } ↓

cause Files loaded via System.import() that contain AMD define() blocks may conflict with SystemJS's own AMD detection.

fix

Ensure all modules are properly defined as ES modules or System.register; avoid anonymous AMD define() calls.

Warnings

breaking In v0.16.0, SystemJS bundles are no longer automatically loaded. You must set useBundles: true in the systemjs config to enable bundle loading. ↓

fix Set systemjs.useBundles: true in your Karma config if you rely on SystemJS bundles.

breaking In v0.9.0, arrays in SystemJS config file are overwritten by arrays in karma config, rather than merged. ↓

fix Ensure that the karma config arrays either contain all needed values or use a different approach to avoid data loss.

gotcha The transpiler (e.g., plugin-babel, traceur) must be served as served:true, included:false in Karma file patterns since v0.13.0. ↓

fix In your SystemJS config, specify the transpiler path under paths or map; karma-systemjs will handle serving automatically.

gotcha PhantomJS v1.x lacks Function.prototype.bind, causing transpiler errors: 'TypeError: undefined is not a function' ↓

fix Install phantomjs-polyfill and include it in your SystemJS config.

deprecated es6-module-loader is deprecated in favor of systemjs itself; modern SystemJS versions may not need it. ↓

fix Consider using SystemJS 0.21+ which includes its own polyfill; remove es6-module-loader dependency if not needed.

Install

npm install karma-systemjs

yarn add karma-systemjs

pnpm add karma-systemjs

Imports

default (plugin)
wrong
```
require('karma-systemjs')
```
correct
```
plugins: ['karma-systemjs']
```
karma-systemjs is a Karma plugin, not imported directly. Add to plugins array in karma.conf.js.
framework (systemjs)
wrong
```
frameworks: ['karma-systemjs']
```
correct
```
frameworks: ['systemjs']
```
Use the short name 'systemjs' in the frameworks array. Must be the first framework in the list.
System (global)
wrong
```
import { System } from 'systemjs'
```
correct
```
System.config({...})
```
System is available globally after loading systemjs, not imported as ES module inside Node.js config files.

Quickstart

Configures Karma to use SystemJS for loading test files via System.import(), with a separate system config file and additional serve files.

// karma.conf.js
module.exports = function(config) {
  config.set({
    frameworks: ['systemjs', 'jasmine'],
    files: [
      'test/**/*.spec.js'
    ],
    plugins: ['karma-systemjs', 'karma-jasmine', 'karma-chrome-launcher'],
    systemjs: {
      configFile: 'system.conf.js',
      serveFiles: [
        'lib/**/*.js'
      ],
      config: {
        paths: {
          'angular-mocks': 'node_modules/angular-mocks/angular-mocks.js'
        }
      },
      useBundles: false
    },
    browsers: ['Chrome']
  });
};