metro-source-map

What is metro-source-map?

The metro-source-map npm package is a component of the Metro bundler, primarily used in React Native applications for handling and transforming source maps. Source maps are files that provide a way to map code within a compressed file back to its original position in a source file. This is especially useful for debugging purposes in a development environment.

What are metro-source-map's main functionalities?

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);

Other packages similar to metro-source-map

source-map

source-map is a comprehensive library for dealing with source maps. It allows for generation, parsing, and manipulation of source maps. Compared to metro-source-map, source-map provides a more extensive set of features for general use cases beyond the React Native ecosystem.

source-map-js

source-map-js is a fork of the original source-map library, optimized for performance. It shares similar functionalities with metro-source-map but is designed to be faster and more efficient in handling source maps in various environments.

README

Metro

🚇 The source map generator for Metro.

(TODO)