istanbul-lib-source-maps

Source Map Consumption

This feature allows for the consumption of source maps by registering them with a source map store. This is useful for tools that need to map coverage information back to the original source files.

const sourceMaps = require('istanbul-lib-source-maps');
const mapStore = sourceMaps.createSourceMapStore();
mapStore.registerURL('compiled.js', 'compiled.js.map');

Source Map Generation

This feature enables the generation of source maps. It's particularly useful for developers who are compiling or transforming their code and need to produce source maps for accurate code coverage reporting.

const {SourceMapGenerator} = require('istanbul-lib-source-maps');
let generator = new SourceMapGenerator({file: 'output.js'});
generator.addMapping({
  generated: {line: 1, column: 0},
  source: 'input.js',
  original: {line: 1, column: 0}
});
let map = generator.toString();

Applying Source Maps to Coverage Data

This feature involves applying source maps to coverage data to remap coverage reports back to the original source code. This is crucial for accurate coverage reporting in projects that use transpilation or other code transformations.

const sourceMaps = require('istanbul-lib-source-maps');
const mapStore = sourceMaps.createSourceMapStore();
mapStore.registerURL('compiled.js', 'compiled.js.map');
const transformedCoverage = mapStore.transformCoverage(mapStore.loadCoverage(coverageObject));