Sign Up for Free

RunKit +

Try any Node.js package right in your browser

This is a playground to test code. It runs a full Node.js environment and already has all of npm’s 400,000 packages pre-installed, including istanbul-instrumenter-loader with all npm packages installed. Try it out:

require("webpack/package.json"); // webpack is a peer dependency. var istanbulInstrumenterLoader = require("istanbul-instrumenter-loader")

This service is provided by RunKit and is not affiliated with npm, Inc or the package authors.

istanbul-instrumenter-loader v3.0.1

Istanbul instrumenter loader for webpack

npm node deps tests coverage chat

Istanbul Instrumenter Loader

Instrument JS files with istanbul-lib-instrument for subsequent code coverage reporting

Install

npm i -D istanbul-instrumenter-loader

Usage

References

Structure

├─ src
│ |– components
│ | |– bar
│ | │ |─ index.js
│ | |– foo/
│     |– index.js
|– test
| |– src
| | |– components
| | | |– foo
| | | | |– index.js

To create a code coverage report for all components (even for those for which you have no tests yet) you have to require all the 1) sources and 2) tests. Something like it's described in "alternative usage" of karma-webpack

test/index.js

// requires all tests in `project/test/src/components/**/index.js`
const tests = require.context('./src/components/', true, /index\.js$/);

tests.keys().forEach(tests);

// requires all components in `project/src/components/**/index.js`
const components = require.context('../src/components/', true, /index\.js$/);

components.keys().forEach(components);

ℹ️ This file will be the only entry point for karma

karma.conf.js

config.set({
  ...
  files: [
    'test/index.js'
  ],
  preprocessors: {
    'test/index.js': 'webpack'
  },
  webpack: {
    ...
    module: {
      rules: [
        // instrument only testing sources with Istanbul
        {
          test: /\.js$/,
          use: { loader: 'istanbul-instrumenter-loader' },
          include: path.resolve('src/components/')
        }
      ]
    }
    ...
  },
  reporters: [ 'progress', 'coverage-istanbul' ],
  coverageIstanbulReporter: {
    reports: [ 'text-summary' ],
    fixWebpackSourcePaths: true
  }
  ...
});

with Babel

You must run the instrumentation as a post step

webpack.config.js

{
  test: /\.js$|\.jsx$/,
  use: {
    loader: 'istanbul-instrumenter-loader',
    options: { esModules: true }
  },
  enforce: 'post',
  exclude: /node_modules|\.spec\.js$/,
}

Options

The loader supports all options supported by istanbul-lib-instrument

NameTypeDefaultDescription
debug{Boolean}falseTurn on debugging mode
compact{Boolean}trueGenerate compact code
autoWrap{Boolean}falseSet to true to allow return statements outside of functions
esModules{Boolean}falseSet to true to instrument ES2015 Modules
coverageVariable{String}__coverage__Name of global coverage variable
preserveComments{Boolean}falsePreserve comments in output
produceSourceMap{Boolean}falseSet to true to produce a source map for the instrumented code
sourceMapUrlCallback{Function}nullA callback function that is called when a source map URL is found in the original code. This function is called with the source filename and the source map URL

webpack.config.js

{
  test: /\.js$/,
  use: {
    loader: 'istanbul-instrumenter-loader',
    options: {...options}
  }
}

Maintainers


Kir Belevich

Juho Vepsäläinen

Joshua Wiens

Michael Ciniawsky

Matt Lewis
RunKit is a free, in-browser JavaScript dev environment for prototyping Node.js code, with every npm package installed. Sign up to share your code.
Sign Up for Free