jridgewell / v8-to-istanbul

convert from v8 coverage format to istanbul's format

v8-to-istanbul

converts from v8 coverage format to istanbul's coverage format.

Usage

const v8toIstanbul = require('v8-to-istanbul')
// the path to the original source-file is required, as its contents are
// used during the conversion algorithm.
const converter = v8toIstanbul('./path-to-instrumented-file.js')
await converter.load() // this is required due to the async source-map dependency.
// provide an array of coverage information in v8 format.
converter.applyCoverage([
  {
    "functionName": "",
    "ranges": [
      {
        "startOffset": 0,
        "endOffset": 520,
        "count": 1
      }
    ],
    "isBlockCoverage": true
  },
  // ...
])
// output coverage information in a form that can
// be consumed by Istanbul.
console.info(JSON.stringify(converter.toIstanbul()))

// cleanup resources allocated in "load" (i.e. by the source-map dependency),
// the converter may not be used anymore afterwards
converter.destroy() 

Ignoring Uncovered Lines

Sometimes you might find yourself wanting to ignore uncovered lines in your application (for example, perhaps you run your tests in Linux, but there's code that only executes on Windows).

To ignore lines, use the special comment /* c8 ignore next */.

ignoring the next line

const myVariable = 99
/* c8 ignore next */
if (process.platform === 'win32') console.info('hello world')

ignoring the next N lines

const myVariable = 99
/* c8 ignore next 3 */
if (process.platform === 'win32') {
  console.info('hello world')
}

ignoring all lines until told

/* c8 ignore start */
function dontMindMe() {
  // ...
}
/* c8 ignore stop */

ignoring the same line as the comment

const myVariable = 99
const os = process.platform === 'darwin' ? 'OSXy' /* c8 ignore next */ : 'Windowsy' 

Testing

To execute tests, simply run:

npm test