babel-plugin-istanbul

by istanbuljs

A babel plugin that adds istanbul instrumentation to ES6 code

475 Stars 60 Forks Last release: Not found BSD 3-Clause "New" or "Revised" License 120 Commits 30 Releases

Available items

No Items, yet!

The developer of this repository has not created any items for sale yet. Need a bug fixed? Help with integration? A different license? Create a request here:

babel-plugin-istanbul

Greenkeeper badge Build Status Coverage Status Conventional Commits community slack

Having problems? want to contribute? join our community slack.

A Babel plugin that instruments your code with Istanbul coverage. It can instantly be used with karma-coverage and mocha on Node.js (through nyc).

Note: This plugin does not generate any report or save any data to any file; it only adds instrumenting code to your JavaScript source code. To integrate with testing tools, please see the Integrations section.

Usage

Install it:

npm install --save-dev babel-plugin-istanbul

Add it to

.babelrc
in test mode:
{
  "env": {
    "test": {
      "plugins": [ "istanbul" ]
    }
  }
}

Optionally, use cross-env to set

NODE_ENV=test
:
{
  "scripts": {
    "test": "cross-env NODE_ENV=test nyc --reporter=lcov --reporter=text mocha test/*.js"
  }
}

Integrations

karma

It just works with Karma. First, make sure that the code is already transpiled by Babel (either using

karma-babel-preprocessor
,
karma-webpack
, or
karma-browserify
). Then, simply set up karma-coverage according to the docs, but don’t add the
coverage
preprocessor.
This plugin has already instrumented your code, and Karma should pick it up automatically.

It has been tested with bemusic/bemuse project, which contains ~2400 statements.

mocha on node.js (through nyc)

Configure Mocha to transpile JavaScript code using Babel, then you can run your tests with

nyc
, which will collect all the coverage report.

babel-plugin-istanbul respects the

include
/
exclude
configuration options from nyc, but you also need to configure NYC not to instrument your code by adding these settings in your
package.json
:
  "nyc": {
    "sourceMap": false,
    "instrument": false
  },

Ignoring files

You don't want to cover your test files as this will skew your coverage results. You can configure this by providing plugin options matching nyc's

exclude
/
include
rules
:

{
  "env": {
    "test": {
      "plugins": [
        ["istanbul", {
          "exclude": [
            "**/*.spec.js"
          ]
        }]
      ]
    }
  }
}

If you don't provide options in your Babel config, the plugin will look for

exclude
/
include
config under an
"nyc"
key in
package.json
.

You can also use istanbul's ignore hints to specify specific lines of code to skip instrumenting.

Source Maps

By default, this plugin will pick up inline source maps and attach them to the instrumented code such that code coverage can be remapped back to the original source, even for multi-step build processes. This can be memory intensive. Set

useInlineSourceMaps
to prevent this behavior.
{
  "env": {
    "test": {
      "plugins": [
        ["istanbul", {
          "useInlineSourceMaps": false
        }]
      ]
    }
  }
}

If you're instrumenting code programatically, you can pass a source map explicitly. ```js import babelPluginIstanbul from 'babel-plugin-istanbul';

function instrument(sourceCode, sourceMap, fileName) { return babel.transform(sourceCode, { filename, plugins: [ [babelPluginIstanbul, { inputSourceMap: sourceMap }] ] }) } ```

Credit where credit is due

The approach used in

babel-plugin-istanbul
was inspired by Thai Pangsakulyanont's original library
babel-plugin-__coverage__
.

babel-plugin-istanbul
for enterprise

Available as part of the Tidelift Subscription.

The maintainers of

babel-plugin-istanbul
and thousands of other packages are working with Tidelift to deliver commercial support and maintenance for the open source dependencies you use to build your applications. Save time, reduce risk, and improve code health, while paying the maintainers of the exact dependencies you use. Learn more.

We use cookies. If you continue to browse the site, you agree to the use of cookies. For more information on our use of cookies please see our Privacy Policy.