perf(@angular/build): optimize sourcemap stripping and loading with buffer fast path - #33816
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This pull request optimizes the JavaScript transformer worker by parsing and stripping trailing sourcemaps directly from raw buffers, avoiding full string decodes and regex scans for the fast path. The reviewer suggests tracking the original sourcemap URL (inputSourceMapUrl) throughout the transformation pipeline to prevent sourcemaps from being silently discarded when no transformations are applied.
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…uffer fast path Optimize sourcemap detection, loading, and stripping during JavaScript transformations by inspecting incoming raw Uint8Array/Buffer data directly before decoding into strings. Files without sourcemap comments are identified via fast Buffer.indexOf() and skip comment removal entirely. For single trailing comments, the sourcemap is parsed directly from the trailing URL slice and the raw code buffer is sliced using a zero-copy subarray view to avoid large string allocations and trailing state-machine scans. Line-start boundaries and end-of-file trailing whitespace are validated to prevent false positives with template strings, safely falling back to full string state-machine parsing when necessary.
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Optimize sourcemap detection, loading, and stripping during JavaScript transformations by inspecting incoming raw Uint8Array/Buffer data directly before decoding into strings.
Files without sourcemap comments are identified via fast Buffer.indexOf() and skip comment removal entirely. For single trailing comments, the sourcemap is parsed directly from the trailing URL slice and the raw code buffer is sliced using a zero-copy subarray view to avoid large string allocations and trailing state-machine scans. Line-start boundaries and end-of-file trailing whitespace are validated to prevent false positives with template strings, safely falling back to full string state-machine parsing when necessary.