seamless js code coverage


A seamless JavaScript code coverage library.

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NOTE: All Pull-Requests must be made into the master branch.

NOTE: Blanket.js will throw XHR cross domain errors if run with the file:// protocol. See Special Features Guide for more details and workarounds.

Please see the following guides for using Blanket.js:




Blanket.js is a code coverage tool for javascript that aims to be:

  1. Easy to install
  2. Easy to use
  3. Easy to understand

Blanket.js can be run seamlessly or can be customized for your needs.

JavaScript code coverage compliments your existing JavaScript tests by adding code coverage statistics (which lines of your source code are covered by your tests).

Blanket works in a 3 step process:

  1. Loading your source files
  2. Parsing the code using Esprima and node-falafel, and instrumenting the file by adding code tracking lines.
  3. Connecting to hooks in the test runner to output the coverage details after the tests have completed.

You've got a few options for using Grunt with Blanket:


A Grunt plugin has been created to allow you to use Blanket like a "traditional" code coverage tool (creating instrumented copies of physical files, as opposed to live-instrumenting). The plugin runs as a standlone project and can be found here.


Runs the QUnit-based Blanket report headlessly using PhantomJS. Results are displayed on the console, and the task will cause Grunt to fail if any of your configured coverage thresholds are not met. Minimum code coverage thresholds can be configured per-file, per-module, and globally.


See the Compatiblity and Feature List including links to working examples.

  1. git clone
  2. npm install
  3. Add your custom build details to the grunt.js file under concat
  4. npm run build

A minified and unminfied copy of the source can be created (see the min task).

All development takes place on the master branch
Your pull request must pass all tests (run npm test to be sure) and respect all existing coverage thresholds

Feel free to add questions to the Issue tracker, or send them to @blanket_js.

Thanks to the many people who have contributed to the project.

And thanks also to: RequireJS, Esprima, node-falafel, Mocha, Qunit.

v1.1.5 - Refactor reporter API.

May 1-13 - 1.1.4
Loaded reverting for grunt-blanket, branch tracking reporter fixed, coverage on-the-go (displaying coverage results while a single page is being used).

Apr 28-13 - 1.1.3 YUI support added with custom adapter (and some wrapping code). CompoundJS support appears to be outside the scope of project.

... (see full revision history)

Copyright (c) 2012-2013 Alex Seville
Licensed under the MIT license.