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perf(source-map): avoid temporary value reconstruction #111

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Merged
luojiyin1987 merged 1 commit into from
Sep 7, 2026
Merged

perf(source-map): avoid temporary value reconstruction #111

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15 changes: 11 additions & 4 deletions src/source-map/build-source-map.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -192,7 +192,13 @@ function buildInlineCodeSegments(
let valueSourceEnd = interior.length;
const leadingEnd = leadingWhitespaceEnd();
const trailingStart = trailingWhitespaceStart();
const hasData = [...interior].some(char => !isWhitespace(char.charCodeAt(0)));
let hasData = false;
for (let i = 0; i < interior.length; i++) {
if (!isWhitespace(interior.charCodeAt(i))) {
hasData = true;
break;
}
}
if (leadingEnd > 0 && trailingStart < interior.length && hasData) {
valueSourceStart = leadingEnd;
valueSourceEnd = trailingStart;
Expand Down Expand Up @@ -249,8 +255,8 @@ function buildUrlSegments(
: undefined;
}
const segments: MarkdownSourceMapSegment[] = [];
let value = '';
let valueOffset = 0;
let valueMatch = true;
const add = (sourceStart: number, sourceEnd: number, output: string, kind: MarkdownSourceMapSegment['kind']) => {
segments.push({
valueStart: valueOffset,
Expand All @@ -259,7 +265,8 @@ function buildUrlSegments(
sourceEnd,
kind,
});
value += output;
if (valueMatch && !node.url.startsWith(output, valueOffset))
valueMatch = false;
valueOffset += output.length;
};
let literalStart = bounds.start;
Expand Down Expand Up @@ -305,7 +312,7 @@ function buildUrlSegments(
offset++;
}
flushLiteral(bounds.end);
return value === node.url ? { segments } : undefined;
return valueMatch && valueOffset === node.url.length ? { segments } : undefined;
}

/**
Expand Down
22 changes: 17 additions & 5 deletions src/source-map/code-segments.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -143,19 +143,33 @@ function trimTrailingLineEnding(md: string, spans: SourceSpan[]): void {
spans.pop();
}

function equalRange(
left: string,
leftStart: number,
right: string,
rightStart: number,
length: number,
): boolean {
for (let i = 0; i < length; i++) {
if (left.charCodeAt(leftStart + i) !== right.charCodeAt(rightStart + i))
return false;
}
return true;
}

function segmentsFromSpans(
md: string,
spans: SourceSpan[],
value: string,
): MarkdownSourceMapSegment[] | undefined {
const segments: MarkdownSourceMapSegment[] = [];
let valueOffset = 0;
let sourceValue = '';
for (const span of spans) {
if (span.start >= span.end)
continue;
const length = span.end - span.start;
sourceValue += md.slice(span.start, span.end);
if (!equalRange(md, span.start, value, valueOffset, length))
return undefined;
const previous = segments[segments.length - 1];
if (previous && previous.sourceEnd === span.start && previous.valueEnd === valueOffset) {
previous.sourceEnd = span.end;
Expand All @@ -172,9 +186,7 @@ function segmentsFromSpans(
}
valueOffset += length;
}
return valueOffset === value.length && sourceValue === value
? segments
: undefined;
return valueOffset === value.length ? segments : undefined;
}

function buildFencedCodeSegments(
Expand Down