Minor Changes

• Add util.sourceMap.originalPositionFor to find the original position of a generated one. (by @alexander-akait in #313)

Patch Changes

• Keep an empty string in sourcesContent instead of dropping it. (by @alexander-akait in #314)

Minor Changes

• Add map({ scopes: true }), emitting the source map scopes field from the bindings a source declares. (by @alexander-akait in #275)

Patch Changes

• Create a cached source's map cache only once a map is asked for. (by @alexander-akait in #296)

Patch Changes

• Hand out a recorded hash update as buffers, so cached data carries no big string. (by @alexander-akait in #289)

Patch Changes

• perf: hash a string-backed source without materializing its buffer (by @alexander-akait in #286)

  RawSource.updateHash and OriginalSource.updateHash called buffer(), which
  encodes the string to UTF-8 and memoizes the result — so every source that was
  hashed kept its content twice, as a string and as a buffer, for as long as the
  source lived. Node hashes a string as UTF-8, the same bytes buffer() produces,
  so the string is hashed directly instead and no digest changes.

  Measured on a webpack build of three.js + lodash-es (1033 modules, 2.71 MB of
  module source): retained arrayBuffers after the build drop from 8.74–8.76 MB
  to 5.81 MB with devtool: false, and from 9.35–12.11 MB to 6.42 MB with
  devtool: "source-map" — disjoint over six and five runs. 1029 Buffer.from
  calls per build are removed, one per module. CPU is unchanged: hashing those
  sources costs 9.23 ms via the buffer against 8.18 ms via the string, which no
  whole-build timing can resolve.

Patch Changes

• perf: stream potential tokens in OriginalSource instead of materialising an array (by @alexander-akait in #246)

  OriginalSource.streamChunks (and therefore map() / sourceAndMap()) previously built the full splitIntoPotentialTokens array of substrings and then iterated it — even though map() and sourceAndMap() run with finalSource: true and discard every chunk substring. The scan is now streamed by offset, so chunk substrings are only allocated when actually emitted. This removes the intermediate array and, on the dominant final-source paths, all per-token slices: map() / sourceAndMap() allocate ~38–46% less memory and run ~15–40% faster.

• Reduce allocations and CPU in map() / sourceAndMap(): mappings are serialized into a reused byte buffer instead of per-mapping strings, ReplaceSource verifies original content through a line-offset index instead of splitting sources into line arrays, and ReplaceSource.streamChunks emits position-only chunks and returns the final source directly when finalSource is requested. (by @alexander-akait in #251)

• Skip sorting ReplaceSource replacements when they were added in order. (by @alexander-akait in #249)

• perf: use lookup table in splitIntoPotentialTokens for faster character classification (by @xiaoxiaojx in #240)

  Replace multi-comparison chains (4 comparisons in phase 1, 6 in phase 2) with a single Uint8Array bitmask lookup per character. This reduces per-character branching overhead, yielding ~7% improvement on typical source and ~21% on large sources.

Minor Changes

• Add clearCache(options?, visited?) method to Source that recursively releases cached data (CachedSource cached maps/buffers/strings, SourceMapSource parsed/serialized map caches, and dual-buffer caches in leaf sources). Lets consumers like webpack's SourceMapDevToolPlugin reclaim memory between chunks rather than accumulating per-task source map data across an entire build. Options: maps (default true) drops cached source maps; source (default true) drops cached source/buffer copies — pass false to keep source available for downstream plugins; parsedMap (default false) additionally drops the parsed object form on SourceMapSource instances when a buffer or string form survives (the combination { maps: true, source: false, parsedMap: true } matches the SourceMapDevToolPlugin call shape in webpack/webpack#20963). The optional visited WeakSet deduplicates the walk when the same child is reachable through multiple parents (e.g. modules shared across chunks). (by @alexander-akait in #221)

Patch Changes

• Implements more effective buffers and buffer for ReplaceSource and improve performance in other places. (by @alexander-akait in #211)

Minor Changes

• Add Source.prototype.buffers() that returns the source as Buffer[]. ConcatSource, CachedSource, and CompatSource implement it without allocating an intermediate concatenated buffer, allowing consumers that can write multiple buffers at once (e.g. via writev) to avoid the overhead of Buffer.concat in deeply nested sources. (by @alexander-akait in #204)

Patch Changes

• fix: use Int32Array for signed VLQ delta accumulation in readMappings so cumulative values that go negative are preserved instead of wrapping to a large unsigned integer (by @alexander-akait in #206)

• Improved performance in many places. (by @alexander-akait in #209)

Fixes

• sync SourceMapSource constructor types with sourceAndMap method (#176)

Fixes

• generate last column mapping even when source is missing for ConcatSource