perf(tokenizer): use String.fromCharCode for BMP characters#1680
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TrevorBurnham wants to merge 1 commit intoinikulin:masterfrom
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perf(tokenizer): use String.fromCharCode for BMP characters#1680TrevorBurnham wants to merge 1 commit intoinikulin:masterfrom
TrevorBurnham wants to merge 1 commit intoinikulin:masterfrom
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Use String.fromCharCode() instead of String.fromCodePoint() for BMP characters (code points < 0x10000) in _emitCodePoint(). This provides a small performance improvement since fromCharCode is simpler and doesn't need to handle surrogate pairs. Characters outside the BMP are rare in HTML content, so the fallback to fromCodePoint is seldom needed.
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This PR optimizes the tokenizer's character emission by using
String.fromCharCode()instead ofString.fromCodePoint()for BMP characters (code points < 0x10000).Motivation
String.fromCharCode()is faster thanString.fromCodePoint()because it's simpler and doesn't need to handle surrogate pairs. Since the vast majority of characters in HTML content fall within the BMP (Basic Multilingual Plane), this optimization targets the common case while maintaining correctness for characters outside the BMP.Changes
_emitCodePoint()in the tokenizer to useString.fromCharCode()for code points < 0x10000String.fromCodePoint()for characters outside the BMP (rare in HTML)Benchmark Results
Results from running
npm run bench-perf(multiple runs averaged):Testing