@srcmap/generator-wasm

High-performance source map generator powered by Rust via WebAssembly.

Builds source maps incrementally by registering sources, names, and mappings. Outputs standard source map v3 JSON (ECMA-426). Alternative to source-map's SourceMapGenerator.

Install

npm install @srcmap/generator-wasm

Works in Node.js, browsers, and any WebAssembly-capable runtime. No native compilation required.

Usage

import { SourceMapGenerator } from '@srcmap/generator-wasm'

const gen = new SourceMapGenerator('bundle.js')

// Register sources and names (returns indices for use in mappings)
const src = gen.addSource('src/app.ts')
gen.setSourceContent(src, 'const x = 1;')

const name = gen.addName('x')

// Add mappings (all positions are 0-based)
gen.addNamedMapping(0, 0, src, 0, 6, name) // generated(0:0) -> original(0:6) name:"x"
gen.addMapping(1, 0, src, 1, 0)            // generated(1:0) -> original(1:0)

// Deduplicated mapping: only adds if different from previous on same line
gen.maybeAddMapping(1, 4, src, 1, 4)

const json = gen.toJSON()

API

new SourceMapGenerator(file?: string)

Create a new source map generator. file is the optional output filename.

Instance methods

| Method | Returns | Description | |--------|---------|-------------| | addSource(source) | number | Register a source file, returns its index | | addName(name) | number | Register a name, returns its index | | setSourceRoot(root) | void | Set the sourceRoot prefix | | setDebugId(id) | void | Set the debug ID (ECMA-426) | | setSourceContent(sourceIdx, content) | void | Attach source content to a source | | addToIgnoreList(sourceIdx) | void | Add a source to the ignoreList | | addGeneratedMapping(genLine, genCol) | void | Add a mapping with no source info | | addMapping(genLine, genCol, src, origLine, origCol) | void | Add a mapping | | addNamedMapping(genLine, genCol, src, origLine, origCol, name) | void | Add a mapping with a name | | maybeAddMapping(genLine, genCol, src, origLine, origCol) | boolean | Add only if different from previous | | toJSON() | string | Generate the source map JSON string |

Instance properties

| Property | Type | Description | |----------|------|-------------| | mappingCount | number | Total number of mappings added |

Build targets

# Node.js (default)
npm run build

# Browser (ES module + .wasm)
npm run build:web

# Bundler (e.g. webpack, vite)
npm run build:bundler

Part of srcmap

High-performance source map tooling written in Rust. See also:

• @srcmap/sourcemap-wasm - Source map parser (WASM)
• @srcmap/remapping-wasm - Concatenation + composition (WASM)
• @srcmap/symbolicate-wasm - Stack trace symbolication (WASM)

License

MIT