Istanbul code coverage loader for Webpack

[](LICENSE)

This is a Webpack loader that uses Istanbul to add code coverage instrumentation to your code. This is especially useful for in-browser testing, in a tool like Karma, where you can use karma-coverage-istanbul-reporter to output code coverage data in a variety of formats that are supported by services like Coveralls or Codacy.

Coverage Istanbul Loader is based on Istanbul Instrumenter Loader, but uses a newer version of the Istanbul API and has better support for source maps.

# Usage

See [the examples folder](examples) for usage examples for various use cases.

- "hello, world" example
  This is the most simplistic example. It just uses coverage-istanbul-loader with its default options to produce an output bundle that contains code coverage instrumentation.
- TypeScript example
  This example demonstrates using coverage-istanbul-loader with transpiled code. It correctly maps the instrumented JavaScript code back to the original TypeScript source code.
- Karma example
  This example demonstrates using coverage-istanbul-loader with Karma and karma-coverage-istanbul-reporter to produce code coverage reports for browser tests.
- Example with options
  This example demonstrates passing options to coverage-istanbul-loader. The options are passed-on to istanbul-lib-instrument, so all the same options are supported.

# Contributing

Contributions, enhancements, and bug-fixes are welcome! Open an issue on GitHub and submit a pull request.

### Building/Testing

To build/test the project locally on your computer:

1. Clone this repo
   `git clone https://github.com/JS-DevTools/coverage-istanbul-loader.git`
2. Install dependencies
   `npm install`
3. Build the code
   `npm run build`
4. Run the tests
   `npm test`

# License

coverage-istanbul-loader is 100% free and open-source, under the [MIT license](LICENSE). Use it however you want.

This package is Treeware. If you use it in production, then we ask that you buy the world a tree to thank us for our work. By contributing to the Treeware forest you’ll be creating employment for local families and restoring wildlife habitats.

# Big Thanks To

Thanks to these awesome companies for their support of Open Source developers ❤