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karma-rollup-preprocessor

library7.0.8jsnpmunverified

Karma preprocessor to bundle ES modules using Rollup. Current stable version 7.0.8 (last released 2021). Release cadence is sporadic with long gaps between major versions. Key differentiators: integrates Rollup into Karma test pipeline, supports all Rollup options, allows multiple configured preprocessors for different transpilation setups. Requires Rollup >=1.0.0 as peer dependency.

testing

npm install karma-rollup-preprocessor

github ↗package ↗

INSTALL

IMPORT

SIG · KARMA-ROLLUP-PREPR

karma-rollup-preprocessor

testingjavascriptv7.0.8

Install

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Import

—

Disk

—

Pass rate

0/ 6

Env Coverage0 / 6

glibc

18–22

musl

18–22

Install & Compatibility

Where this runs

tested against v? · npm install

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

node 18–223 runs

build_error

glibc

node 18–223 runs

build_error

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

rollupPreprocessor

✓ config.set({ rollupPreprocessor: { ... } })

✗ module.exports = { rollupPreprocessor: ... }

Configuration is set inside Karma config function, not exported directly.

rollup

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

✗ preprocessors: { 'test/**/*.spec.js': ['rollupPreprocessor'] }

The preprocessor name is 'rollup', not 'rollupPreprocessor'. The configuration key is 'rollupPreprocessor'.

customPreprocessors

✓ customPreprocessors: { rollupBabel: { base: 'rollup', options: { ... } } }

✗ customPreprocessors: { rollupBabel: { base: 'rollupPreprocessor', options: { ... } } }

The base preprocessor is referenced as 'rollup', not 'rollupPreprocessor'.

Basic Karma configuration with rollupPreprocessor for bundling test files.

// karma.conf.js module.exports = function(config) { config.set({ files: [ { pattern: 'test/**/*.spec.js', watched: false } ], preprocessors: { 'test/**/*.spec.js': ['rollup'] }, rollupPreprocessor: { plugins: [ require('rollup-plugin-commonjs')(), require('rollup-plugin-node-resolve')() ], output: { format: 'iife', name: 'MyTest', sourcemap: 'inline' } } }); };

Debug

Known issues

deprecatedrollup-plugin-buble and rollup-plugin-babel are no longer maintained; use @rollup/plugin-buble and @rollup/plugin-babel instead.

fix

Replace require('rollup-plugin-buble') with require('@rollup/plugin-buble') and update configuration accordingly.

affects: >=2.0.0

gotchaKarma's file watcher must be disabled for files processed by rollupPreprocessor (watched: false).

fix

Set `watched: false` in the files array for patterns handled by rollup preprocessor.

affects: >=1.0.0

gotchaThe Rollup input option is handled automatically; setting it manually can cause issues.

fix

Do not specify `input` in rollupPreprocessor options; the preprocessor sets it to each test file.

affects: >=2.0.0

gotchaSource map file paths may be incorrect on Windows when using absolute paths.

fix

Use relative paths or update to version 7.0.8 which includes a fix.

affects: >=6.0.0

Errors

Common errors & fixes

Error: Invalid configuration: preprocessors.rollup expected a string or an array of strings.

Preprocessor name used incorrectly (e.g., 'rollupPreprocessor' instead of 'rollup').

fix

In preprocessors config, use 'rollup' as the preprocessor name, not 'rollupPreprocessor'.

TypeError: Cannot read property 'plugins' of undefined

rollupPreprocessor object is missing or not correctly placed in Karma config.

fix

Ensure rollupPreprocessor is defined inside config.set({...}) as a top-level key.

Error: ENOENT: no such file or directory, open '...'

Input file not found because Rollup is trying to resolve a missing module.

fix

Install missing npm packages and configure resolve plugins (e.g., @rollup/plugin-node-resolve).

Upgrade

Version history

7.0.8latest on npm

Audit

Dependencies

rolluprequiredpeer dependency; used for bundling ES modules

Agent activity

9 hits · last 30 days

node

Resources

githubhttps://github.com/jlmakes/karma-rollup-preprocessor ↗

packagehttps://www.npmjs.com/package/karma-rollup-preprocessor ↗