About Istanbul
Istanbul is a JavaScript code coverage tool. It instruments your ES5 and ES2015+ code with counters, so you can see how much of it your tests run.
What it does
Istanbul works with popular test frameworks such as Mocha, tap and AVA through the nyc command line client. Coverage is reported in the terminal and as HTML pages, and the tool can follow subprocesses started during a test run. Support for modern JavaScript comes from a Babel plugin, so newer syntax is measured as well.
Key features
- Instruments ES5 and ES2015+ code
- Terminal and HTML coverage reports
- nyc command line client
- Coverage for subprocesses
Who it's for
JavaScript and Node.js teams that want coverage numbers for their unit tests and integration tests.
Pricing and good to know
Istanbul is open source, and the nyc client is on GitHub under the ISC license. The GitHub repository has about 5.8k stars. To add coverage to Mocha tests, you install nyc as a dev dependency and put the nyc prefix in front of your test command.
Highlights
- Instrument ES5 and ES2015+ code
- Report coverage in the terminal or HTML
- Use the nyc command line client
- Measure coverage in subprocesses
