Istanbul

Spec sheet

Purpose

Istanbul instruments JavaScript code with line counters to track how well unit tests exercise a codebase.Read 11 Oct 2026 · istanbul.js.org

Integrations

Listed integrations are nyc, c8, Jest and node-tap; c8 uses Istanbul reports to display V8 coverage.Read 11 Oct 2026 · istanbul.js.org

Support

The contributing page directs users to report bugs by opening an issue in the appropriate GitHub repository.Read 10 Oct 2026 · istanbul.js.org

License

The Istanbul site identifies its license as Revised BSD License.Read 11 Oct 2026 · istanbul.js.org

Advanced features

Advanced documentation links to source instrumentation, process tree information, reports from a __coverage__ object and alternative reporters.Read 11 Oct 2026 · istanbul.js.org

CLI use

The quick start installs nyc as a development dependency and shows running it before mocha in a test script.Read 11 Oct 2026 · istanbul.js.org

Configurable reports

The nyc README says reporters can be built in or supplied by an npm package, and defaults to text output.Read 11 Oct 2026 · github.com

ES2015+ support

The site lists first-class ES6/ES2015+ support through babel-plugin-istanbul.Read 10 Oct 2026 · istanbul.js.org

ES6 support

The site lists first class ES6/ES2015+ support through babel-plugin-istanbul.Read 11 Oct 2026 · istanbul.js.org

JavaScript support

The site says Istanbul instruments ES5 and ES2015+ JavaScript.Read 10 Oct 2026 · istanbul.js.org

Open source project

The Istanbul GitHub organization describes Istanbul as a JavaScript code coverage tool that computes statement, line, function and branch coverage.Read 11 Oct 2026 · github.com

Other framework support

The homepage says nyc works with testing frameworks including tap, mocha, and AVA.Read 10 Oct 2026 · istanbul.js.org

Reports

Istanbul provides reporters with terminal and HTML output.Read 11 Oct 2026 · istanbul.js.org

Setup

The quick start installs nyc as a development dependency with npm and shows using it before a mocha test command.Read 10 Oct 2026 · istanbul.js.org

Source mapped coverage

The nyc README lists source mapped coverage for Babel and TypeScript projects.Read 11 Oct 2026 · github.com

Subprocesses

The site lists support for instrumenting subprocesses through the nyc command line interface.Read 11 Oct 2026 · istanbul.js.org

Supported JavaScript

The site says Istanbul instruments ES5 and ES2015+ JavaScript.Read 11 Oct 2026 · istanbul.js.org

Test frameworks

The nyc client works with most JavaScript testing frameworks, and the site names tap, mocha and AVA as examples.Read 11 Oct 2026 · istanbul.js.org

Testing integrations

The integrations page lists nyc, c8, Jest, and node-tap as tools that integrate with Istanbul APIs for JavaScript test coverage.Read 10 Oct 2026 · istanbul.js.org

Tutorials

The tutorials cover AVA, ES2015+, Jest, mocha, Intern, IoT.js, tap and TypeScript.Read 11 Oct 2026 · istanbul.js.org

Where Specifiction places it

• Test Coverage Tools#23 of 276.9