karma-vite

library1.0.5jsnpmunverified

A Karma plugin that uses Vite to transform ES modules for testing. Current stable version is 1.0.5, released December 2023, supporting Vite 2 through 5. It enables using Vite's fast development server and module transformation within Karma test runner. Unlike karma-webpack or karma-rollup, it leverages Vite's on-demand compilation and HMR-like middleware for quicker test re-runs. Requires Karma 6+ and Vite 2-5 as peer dependencies. Ships TypeScript types.

testing

npm install karma-vite

github ↗package ↗

INSTALL

IMPORT

SIG · KARMA-VITE

karma-vite

testingjavascriptv1.0.5

Install

—

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.

karma-vite

✓ module.exports = (config) => { config.set({ plugins: ['karma-vite'], frameworks: ['vite'] }); };

✗ const karmaVite = require('karma-vite');

The plugin is a Karma framework plugin; it should be registered via 'plugins' array in karma.conf.js, not required directly in test files.

KarmaViteConfig

✓ import type { KarmaViteConfig } from 'karma-vite';

✗ const { KarmaViteConfig } = require('karma-vite');

TypeScript users can import the KarmaViteConfig interface for configuring the vite property in karma.conf.js. CJS require is not supported for types; use import type.

karma-vite (as a plugin)

✓ plugins: ['karma-vite']

✗ plugins: [require('karma-vite')]

Karma resolves plugin names from npm packages; using require() for the plugin object is unnecessary and can break plugin resolution.

Minimal Karma configuration to run Jasmine tests with Vite transformation. Tests are ES modules with .ts extension, and Vite handles TypeScript compilation.

// karma.conf.js module.exports = (config) => { config.set({ plugins: ['karma-vite', 'karma-jasmine'], frameworks: ['vite', 'jasmine'], files: [ { pattern: 'test/**/*.spec.ts', type: 'module', watched: false, served: false, }, ], }); };

Debug

Known issues

gotchaThe files pattern must include type: 'module', watched: false, and served: false. Missing these can cause infinite loops or modules not being served.

fix

Set type: 'module', watched: false, served: false on all test file entries.

affects: >=1.0.0

breakingKarma testing never starts if urlRoot is the default value ('/') in Karma config.

fix

Upgrade to 1.0.1 or later. Alternatively, set urlRoot to a non-root path (e.g., '/karma/').

affects: 1.0.0

deprecatedSupport for Vite 2 was removed in v1.0.5 (since Vite 2 is no longer maintained).

fix

Use Vite 3, 4, or 5 with karma-vite >=1.0.5.

affects: >=1.0.5

gotchaviteClientMiddleware always calls next() even when it should not, causing middleware chaining issues in some Karma setups.

fix

Upgrade to 1.0.3 or later.

affects: >=1.0.0 <1.0.3

gotchaVite define variables are not applied when using karma-vite v1.0.0.

fix

Upgrade to 1.0.1 or later.

affects: 1.0.0

gotchaCoverage reports can be generated via vite-plugin-istanbul, but only if 'coverage' reporter is present in Karma config. If coverage reporter is not configured, coverage instrumentation may silently not work.

fix

Ensure karma-coverage plugin is installed and add 'coverage' to reporters array in Karma config.

affects: >=1.0.0

Errors

Common errors & fixes

Karma never starts. Tests are not executed.

urlRoot is set to default '/' in Karma config, which conflicts with karma-vite middleware.

fix

Set urlRoot to a non-root path (e.g., '/karma/') in karma.conf.js, or upgrade to karma-vite v1.0.1+.

Cannot find module 'karma-vite'

Plugin not installed or not registered correctly in karma config.

fix

Run 'npm install -D karma-vite'. Ensure 'karma-vite' is listed in the plugins array (not require()'d directly).

TypeError: Cannot read properties of undefined (reading 'call')

viteClientMiddleware receives an undefined response object due to middleware chain issues (affects v1.0.0–1.0.2).

fix

Upgrade to karma-vite v1.0.3 or later.

Vite config 'define' not working. Environment variables are undefined in tests.

Bug in karma-vite v1.0.0 where Vite's define config is ignored.

fix

Upgrade to karma-vite v1.0.1 or later.

Upgrade

Version history

1.0.5latest on npm

Audit

Dependencies

karmarequiredPeer dependency; Karma test runner required to run tests

viterequiredPeer dependency; Vite is used for module transformation and dev server

Agent activity

4 hits · last 30 days

node

Resources

githubhttps://github.com/credred/karma-vite ↗

packagehttps://www.npmjs.com/package/karma-vite ↗