@srcmap/codec

High-performance VLQ source map codec powered by Rust via NAPI.

Drop-in replacement for @jridgewell/sourcemap-codec. Encodes and decodes source map mappings strings as specified in ECMA-426.

Install

npm install @srcmap/codec

Prebuilt binaries are available for:

• macOS (x64, arm64)
• Linux (x64, arm64, glibc + musl)
• Windows (x64)

Usage

import { decode, encode } from '@srcmap/codec';

const decoded = decode('AAAA;AACA,EAAE');
// [
//   [[0, 0, 0, 0]],
//   [[0, 0, 1, 0], [2, 0, 0, 2]]
// ]

const encoded = encode(decoded);
// 'AAAA;AACA,EAAE'

API

decode(mappings: string): number[][][]

Decode a VLQ-encoded mappings string into an array of lines, each containing an array of segments. Each segment is an array of 1, 4, or 5 numbers.

encode(mappings: number[][][]): string

Encode decoded mappings back into a VLQ string.

Segment format

| Fields | Meaning | |--------|---------| | [genCol] | Generated column only | | [genCol, srcIdx, origLine, origCol] | With source mapping | | [genCol, srcIdx, origLine, origCol, nameIdx] | With source mapping and name |

Compatibility

API-compatible with @jridgewell/sourcemap-codec — same function signatures, same output format. Can be used as a drop-in replacement.

Part of srcmap

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

• @srcmap/sourcemap - Source map parser (NAPI)
• @srcmap/sourcemap-wasm - Source map parser (WASM)

License

MIT