karma-rollup-preprocessor

Karma preprocessor to bundle ES modules using Rollup.

Installation

``bash
npm install karma-rollup-preprocessor
`

Configuration

All the options detailed in the Rollup Documentation can be passed to rollupPreprocessor.

$3

Below is a well-founded recommendation using the Bublé ES2015 transpiler:

`js
// karma.conf.js
module.exports = function (config) {
config.set({
files: [
/**
* Make sure to disable Karma’s file watcher
* because the preprocessor will use its own.
*/
{ pattern: 'test/*/.spec.js', watched: false },
],

preprocessors: {
'test/*/.spec.js': ['rollup'],
},

rollupPreprocessor: {
/**
* This is just a normal Rollup config object,
* except that input is handled for you.
*/
plugins: [require('rollup-plugin-buble')()],
output: {
format: 'iife', // Helps prevent naming collisions.
name: '', // Required for 'iife' format.
sourcemap: 'inline', // Sensible for testing.
},
},
})
}
`

$3

Below shows an example where configured preprocessors can be very helpful:

`js
// karma.conf.js
module.exports = function (config) {
config.set({
files: [{ pattern: 'test/*/.spec.js', watched: false }],

preprocessors: {
'test/buble/*/.spec.js': ['rollup'],
'test/babel/*/.spec.js': ['rollupBabel'],
},

rollupPreprocessor: {
plugins: [require('rollup-plugin-buble')()],
output: {
format: 'iife',
name: '',
sourcemap: 'inline',
},
},

customPreprocessors: {
/**
* Clones the base preprocessor, but overwrites
* its options with those defined below...
*/
rollupBabel: {
base: 'rollup',
options: {
// In this case, to use a different transpiler:
plugins: [require('rollup-plugin-babel')()],
},
},
},
})
}
``

Happy bundling! !heart