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Everyone's favorite JS code coverage tool.

About this Repo

This monorepo contains the nuts and bolts utility libraries that facilitate IstanbulJS test coverage; Why a monorepo?

  • it allows us to more easily test API changes across coupled modules, e.g., changes to istanbul-lib-coverage potentially have an effect on istanbul-lib-instrument.
  • it gives us a centralized repo for discussions about bugs and upcoming features.

Where Should I Start

You're probably actually looking for one of the following repos:

  • nyc: the IstanbulJS 2.0 command line interface, providing painless coverage support for most popular testing frameworks.
  • babel-plugin-istanbul: a babel plugin for instrumenting your ES2015+ code with Istanbul compatible coverage tracking.
  • istanbul: the legacy 1.0 IstanbulJS interface (you should now consider instead using nyc or babel-plugin-istanbul).


Contributing to the packages contained in this repo is easy:

  1. after checking out, run npm install (this will run the lerna build).
  2. to run all tests, simply run npm test in the root directory.
  3. to run tests for a single package cd package/:name and run npm test within the package's folder.