Code coverage for Jest built on top of Jasmine

When using Jest 21.2.1, I can see code coverage at the command line and create a coverage directory by passing --coverage to the Jest script. Below are some examples:

I tend to install Jest locally, in which case the command might look like this:

npx jest --coverage

I assume (though haven't confirmed), that this would also work if I installed Jest globally:

jest --coverage

The very sparse docs are here

When I navigated into the coverage/lcov-report directory I found an index.html file that could be loaded into a browser. It included the information printed at the command line, plus additional information and some graphical output.

UPDATE: 7/20/2018 - Added links and updated name for coverageReporters.

UPDATE: 8/14/2017 - This answer is totally outdated. Just look at the Jest docs now. They have official support and documentation about how to do this.

@hankhsiao has got a forked repo where Istanbul is working with Jest. Add this to your dev dependencies

 "devDependencies": {
     "jest-cli": "git://github.com/hankhsiao/jest.git"
 }

Also make sure coverage is enabled in your package.json jest entry and you can also specify formats you want. (The html is pretty bad ass).

 "jest": {
     "collectCoverage": true,
     "coverageReporters": ["json", "html"],
 }

See Jest documentation for coverageReporters (default is ["json", "lcov", "text"])

Or add --coverage when you invoke jest.

Jan 2019: Jest version 23.6

For anyone looking into this question recently especially if testing using npm or yarn directly

Currently, you don't have to change the configuration options

As per Jest official website, you can do the following to generate coverage reports:

1- For npm:

You must put -- before passing the --coverage argument of Jest

npm test -- --coverage

if you try invoking the --coverage directly without the -- it won't work

2- For yarn:

You can pass the --coverage argument of jest directly

yarn test --coverage