esnext-coverage

Modular coverage tools for the modern web.

Installation

npm install --save-dev esnext-coverage

Usage with test frameworks

See esnext-coverage-examples repository for more details.

Tape

Require esnext-coverage when running Tape:

tape -r esnext-coverage test/*.js

Mocha

Require esnext-coverage when running Mocha:

mocha -r esnext-coverage test/*.js

Jasmine

Replace babel-register with esnext-coverage in the list of Jasmine helpers:

"helpers": [
  "../node_modules/esnext-coverage/lib/esnext-coverage.js"
]

Options

The esnext-coverage configuration is an object that extends Babel API options with two additional properties:

reporters

A reporter signature is an object containing formatter (String or Function, defaults to JSON.stringify), console (Boolean, defaults to false) and outFile (String, optional) properties.

When formatter is a String, esnext-coverage will attempt to require(`esnext-coverage-format-${formatter}`) similar to Babel requiring plugins.

reporters: [
  // Format using esnext-coverage-format-text,
  // and write the formatted output to stdout:
  {formatter: 'text', console: true},
  // Format using esnext-coverage-format-html,
  // and write the formatted output to a file:
  {formatter: 'html', outFile: 'reports/coverage/coverage.html'},
  // Format using a custom formatter function,
  // and write the formatted output to a file:
  {formatter: myFormatter, outFile: 'reports/coverage/coverage.my'}
]

If reporters are not specified, a default reporter is used with 'json' as formatter and 'reports/coverage/coverage.json' file as output:

reporters: [
  {formatter: 'json', outFile: 'reports/coverage/coverage.json'}
]

thresholds

Both global and local properties are optional. No threshold is enforced by default.

thresholds: {
  global: {
    statement: 100,
    branch: 100,
    function: 100,
    line: 100
  },
  local: {
    statement: 100,
    branch: 100,
    function: 100,
    line: 100
  }
}

Configuration

Add an "esnext-coverage": {...options} entry in your package.json file or create either .esnextcoverage.js or .esnextcoveragerc file in the root of your project.

package.json

{
  "name": "my project",
  "version": "1.2.3",
  "esnext-coverage": {
    "only": "test/*.js",
    "reporters": [
      {"formatter": "text", "console": true}
    ]
  }
}

.esnextcoverage.js

module.exports = {
  only: 'test/*.js',
  reporters: [
    {formatter: 'text', console: true}
  ]
};

.esnextcoveragerc

{
  "only": "test/*.js",
  "reporters": [
    {"formatter": "text", "console": true}
  ]
}

CLI usage

Usage: esnext-coverage [options] [command]

Commands:

  instrument [options] [file]  instruments code
  collect [options] [file]     collects coverage data
  format [options] [file]      formats coverage data

Options:

  -h, --help     output usage information
  -V, --version  output the version number

instrument

Reads code from stdin or from a file, instruments it, and writes the instrumented code to stdout or to a file.

collect

Reads code from stdin or from a file, collects coverage data, and writes the result to stdout or to a file.

format

Transforms coverage data to the specified format.

Prior art

esnext-coverage has been inspired by Adana.

License

MIT License