karma-babel-preprocessor

Karma preprocessor to compile ES6+ on the fly with Babel. Version 8.0.2, stable, maintained as part of the Babel ecosystem. Requires @babel/core 7 as a peer dependency. Use with Babel presets to transpile modern JavaScript during test runs. Not a module bundler; for CommonJS you need a separate bundler like webpack or browserify. Key differentiator: seamless integration with Karma test runner, supports per-file Babel options via function properties.