Registry / testing / karma-esbuild-next

karma-esbuild-next

library1.1.0jsnpmunverified

An esbuild preprocessor for the Karma test runner, forked from karma-esbuild. It leverages esbuild for fast compilation and readable output, supporting custom esbuild configurations, plugin integration, and single-bundle mode to merge test files into one bundle. Current version 1.1.0 requires esbuild >=0.17.0. Compared to alternatives like karma-webpack or karma-rollup, it offers significantly faster build times due to esbuild's speed, while maintaining compatibility with Karma's standard preprocessor interface.

testing

npm install karma-esbuild-next

github ↗package ↗

INSTALL

IMPORT

SIG · KARMA-ESBUILD-NEXT

karma-esbuild-next

testingjavascriptv1.1.0

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

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

karma-esbuild-next

✓ npm install --save-dev karma-esbuild-next

✗ npm install --save-dev karma-esbuild

Install the package, then configure in karma.conf.js

config.set({ preprocessors: { "test/**/*.test.js": ["esbuild"] } })

✓ preprocessors: { "test/**/*.test.js": ["esbuild"] }

✗ preprocessors: { "test/**/*.test.js": ["karma-esbuild-next"] }

The preprocessor name is 'esbuild', not the package name

esbuild config block

✓ config.set({ esbuild: { define: {}, plugins: [], singleBundle: true } })

✗ config.set({ esbuild: { bundle: true } })

Use 'singleBundle' for bundling test files; 'bundle' is an esbuild option but not directly supported

Configure Karma to use esbuild preprocessor with Mocha, a define variable, and single bundle mode.

// karma.conf.js module.exports = function (config) { config.set({ frameworks: ['mocha'], files: ['test/**/*.test.js'], preprocessors: { 'test/**/*.test.js': ['esbuild'] }, plugins: [ 'karma-esbuild-next' ], esbuild: { define: { 'process.env.NODE_ENV': JSON.stringify('test') }, singleBundle: true }, browsers: ['ChromeHeadless'], singleRun: true }); };

Debug

Known issues

gotchaPreprocessor name must be 'esbuild', not the package name

fix

Use 'esbuild' in preprocessors array, not 'karma-esbuild-next'

affects: >=1.0.0

breakingRequires esbuild >=0.17.0; older versions may fail

fix

Update esbuild to version 0.17.0 or later

affects: >=1.0.0

gotchasingleBundle defaults to true; all test files are bundled into one. This can cause issues if tests rely on separate scopes for globals.

fix

Set singleBundle: false if you need separate bundles per test file

affects: >=1.0.0

deprecatedThe original karma-esbuild package is unmaintained; this fork is the recommended alternative

fix

Switch to karma-esbuild-next

affects: >=0.0.0

Errors

Common errors & fixes

Error: No provider for "framework:esbuild"! (Resolving: esbuild)

Missing 'esbuild' in preprocessors array incorrectly, or plugin not installed

fix

Ensure you have added 'karma-esbuild-next' to plugins array in karma.conf.js

Error: Cannot find module 'karma-esbuild-next'

Package not installed or not listed in package.json devDependencies

fix

Run 'npm install --save-dev karma-esbuild-next'

Error: esbuild: Unexpected option: bundle

Using esbuild 'bundle' option inside esbuild config block in karma.conf.js

fix

Use 'singleBundle' instead of 'bundle' for Karma-specific bundling

Upgrade

Version history

1.1.0latest on npm

Audit

Dependencies

esbuildrequiredpeer dependency: esbuild is required for compilation

Agent activity

6 hits · last 30 days

node

Resources

githubhttps://github.com/alexandernst/karma-esbuild-next ↗

packagehttps://www.npmjs.com/package/karma-esbuild-next ↗