karma-esbuild

An esbuild preprocessor for the karma test runner. The main benefits of esbuild is speed and readability of the compiled output.

Installation

npm install --save-dev karma-esbuild

Usage

Add esbuild as your preprocessor inside your karma.conf.js:

module.exports = function (config) {
    config.set({
        preprocessors: {
            // Add esbuild to your preprocessors
            "test/**/*.test.js": ["esbuild"],
        },
    });
};

Advanced: Custom configuration

A custom esbuild configuration can be passed via an additional property on karma's config. Check out the documentation for esbuild for available options.

module.exports = function (config) {
    config.set({
        preprocessors: {
            // Add esbuild to your preprocessors
            "test/**/*.test.js": ["esbuild"],
        },

        esbuild: {
            // Replace some global variables
            define: {
                COVERAGE: coverage,
                "process.env.NODE_ENV": JSON.stringify(process.env.NODE_ENV || ""),
                ENABLE_PERFORMANCE: true,
            },
            plugins: [createEsbuildPlugin()],

            // Karma-esbuild specific options
            singleBundle: true, // Merge all test files into one bundle(default: true)
        },
    });
};

License

MIT, see the LICENSE file.