perf - speed up quick open scorer by ~10%

Move some computations out of the inner loop into the outer loop to avoid repeated computation.

src/vs/base/parts/quickopen/common/quickOpenScorer.ts

@@ -60,7 +60,7 @@ export function score(target: string, query: string, queryLower: string, fuzzy:
 	return res;
 }
 
-function doScore(query: string, queryLower: string, queryLength: number, target: string, targetLower: string, targetLength: number): [number, number[]] {
+function doScore(query: string, queryLower: string, queryLength: number, target: string, targetLower: string, targetLength: number): Score {
 	const scores: number[] = [];
 	const matches: number[] = [];
 
@@ -80,15 +80,25 @@ function doScore(query: string, queryLower: string, queryLength: number, target:
 	//  y
 	//
 	for (let queryIndex = 0; queryIndex < queryLength; queryIndex++) {
+		const queryIndexOffset = queryIndex * targetLength;
+		const queryIndexPreviousOffset = queryIndexOffset - targetLength;
+
+		const queryIndexGtNull = queryIndex > 0;
+
+		const queryCharAtIndex = query[queryIndex];
+		const queryLowerCharAtIndex = queryLower[queryIndex];
+
 		for (let targetIndex = 0; targetIndex < targetLength; targetIndex++) {
-			const currentIndex = queryIndex * targetLength + targetIndex;
+			const targetIndexGtNull = targetIndex > 0;
+
+			const currentIndex = queryIndexOffset + targetIndex;
 			const leftIndex = currentIndex - 1;
-			const diagIndex = (queryIndex - 1) * targetLength + targetIndex - 1;
+			const diagIndex = queryIndexPreviousOffset + targetIndex - 1;
 
-			const leftScore: number = targetIndex > 0 ? scores[leftIndex] : 0;
-			const diagScore: number = queryIndex > 0 && targetIndex > 0 ? scores[diagIndex] : 0;
+			const leftScore = targetIndexGtNull ? scores[leftIndex] : 0;
+			const diagScore = queryIndexGtNull && targetIndexGtNull ? scores[diagIndex] : 0;
 
-			const matchesSequenceLength: number = queryIndex > 0 && targetIndex > 0 ? matches[diagIndex] : 0;
+			const matchesSequenceLength = queryIndexGtNull && targetIndexGtNull ? matches[diagIndex] : 0;
 
 			// If we are not matching on the first query character any more, we only produce a
 			// score if we had a score previously for the last query index (by looking at the diagScore).
@@ -96,10 +106,10 @@ function doScore(query: string, queryLower: string, queryLength: number, target:
 			// given a target of "ede" and a query of "de", we would otherwise produce a wrong high score
 			// for query[1] ("e") matching on target[0] ("e") because of the "beginning of word" boost.
 			let score: number;
-			if (!diagScore && queryIndex > 0) {
+			if (!diagScore && queryIndexGtNull) {
 				score = 0;
 			} else {
-				score = computeCharScore(query, queryLower, queryIndex, target, targetLower, targetIndex, matchesSequenceLength);
+				score = computeCharScore(queryCharAtIndex, queryLowerCharAtIndex, target, targetLower, targetIndex, matchesSequenceLength);
 			}
 
 			// We have a score and its equal or larger than the left score
@@ -146,10 +156,10 @@ function doScore(query: string, queryLower: string, queryLength: number, target:
 	return [scores[queryLength * targetLength - 1], positions.reverse()];
 }
 
-function computeCharScore(query: string, queryLower: string, queryIndex: number, target: string, targetLower: string, targetIndex: number, matchesSequenceLength: number): number {
+function computeCharScore(queryCharAtIndex, queryLowerCharAtIndex, target: string, targetLower: string, targetIndex: number, matchesSequenceLength: number): number {
 	let score = 0;
 
-	if (queryLower[queryIndex] !== targetLower[targetIndex]) {
+	if (queryLowerCharAtIndex !== targetLower[targetIndex]) {
 		return score; // no match of characters
 	}
 
@@ -170,7 +180,7 @@ function computeCharScore(query: string, queryLower: string, queryIndex: number,
 	}
 
 	// Same case bonus
-	if (query[queryIndex] === target[targetIndex]) {
+	if (queryCharAtIndex === target[targetIndex]) {
 		score += 1;
 
 		// if (DEBUG) {