metro-source-map

Source Map Generation

Generate a source map from raw mappings. This feature is crucial for creating source maps that help in debugging by mapping the transformed code back to the original source code.

const { fromRawMappings } = require('metro-source-map');
const mappings = [{
  generated: { line: 1, column: 5 },
  original: { line: 1, column: 5 },
  source: 'source.js'
}];
const sourceMap = fromRawMappings(mappings).toString();

Source Map Composition

Compose multiple source maps into a single source map. This is useful when dealing with transformations or optimizations that occur in multiple stages, allowing for a unified source map that reflects all changes.

const { composeSourceMaps } = require('metro-source-map');
const firstMap = { version: 3, sources: ['foo.js'], names: [], mappings: 'AAAA' };
const secondMap = { version: 3, sources: ['foo.js'], names: [], mappings: 'BBBB' };
const composedMap = composeSourceMaps(firstMap, secondMap);