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Cache the length of arrays in core utilities. #58920

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Cache the length of arrays in core utilities. #58920

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67 changes: 33 additions & 34 deletions src/compiler/core.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -11,8 +11,6 @@ import {
TextSpan,
} from "./_namespaces/ts.js";

/* eslint-disable @typescript-eslint/prefer-for-of */

/** @internal */
export const emptyArray: never[] = [] as never[];
/** @internal */
Expand All @@ -34,7 +32,7 @@ export function length(array: readonly any[] | undefined): number {
*/
export function forEach<T, U>(array: readonly T[] | undefined, callback: (element: T, index: number) => U | undefined): U | undefined {
if (array !== undefined) {
for (let i = 0; i < array.length; i++) {
for (let i = 0, n = array.length; i < n; i++) {
const result = callback(array[i], i);
if (result) {
return result;
Expand Down Expand Up @@ -71,7 +69,7 @@ export function firstDefined<T, U>(array: readonly T[] | undefined, callback: (e
return undefined;
}

for (let i = 0; i < array.length; i++) {
for (let i = 0, n = array.length; i < n; i++) {
const result = callback(array[i], i);
if (result !== undefined) {
return result;
Expand Down Expand Up @@ -108,7 +106,7 @@ export function reduceLeftIterator<T, U>(iterator: Iterable<T> | undefined, f: (
export function zipWith<T, U, V>(arrayA: readonly T[], arrayB: readonly U[], callback: (a: T, b: U, index: number) => V): V[] {
const result: V[] = [];
Debug.assertEqual(arrayA.length, arrayB.length);
for (let i = 0; i < arrayA.length; i++) {
for (let i = 0, n = arrayA.length; i < n; i++) {
result.push(callback(arrayA[i], arrayB[i], i));
}
return result;
Expand Down Expand Up @@ -146,7 +144,7 @@ export function every<T, U extends T>(array: readonly T[] | undefined, callback:
export function every<T>(array: readonly T[] | undefined, callback: (element: T, index: number) => boolean): boolean;
export function every<T>(array: readonly T[] | undefined, callback: (element: T, index: number) => boolean): boolean {
if (array !== undefined) {
for (let i = 0; i < array.length; i++) {
for (let i = 0, n = array.length; i < n; i++) {
if (!callback(array[i], i)) {
return false;
}
Expand Down Expand Up @@ -237,7 +235,7 @@ export function findMap<T, U>(array: readonly T[], callback: (element: T, index:
/** @internal */
export function contains<T>(array: readonly T[] | undefined, value: T, equalityComparer: EqualityComparer<T> = equateValues): boolean {
if (array !== undefined) {
for (let i = 0; i < array.length; i++) {
for (let i = 0, n = array.length; i < n; i++) {
if (equalityComparer(array[i], value)) {
return true;
}
Expand All @@ -260,7 +258,7 @@ export function indexOfAnyCharCode(text: string, charCodes: readonly number[], s
export function countWhere<T>(array: readonly T[] | undefined, predicate: (x: T, i: number) => boolean): number {
let count = 0;
if (array !== undefined) {
for (let i = 0; i < array.length; i++) {
for (let i = 0, n = array.length; i < n; i++) {
const v = array[i];
if (predicate(v, i)) {
count++;
Expand Down Expand Up @@ -316,7 +314,7 @@ export function filter<T>(array: readonly T[] | undefined, f: (x: T) => boolean)
/** @internal */
export function filterMutate<T>(array: T[], f: (x: T, i: number, array: T[]) => boolean): void {
let outIndex = 0;
for (let i = 0; i < array.length; i++) {
for (let i = 0, n = array.length; i < n; i++) {
if (f(array[i], i, array)) {
array[outIndex] = array[i];
outIndex++;
Expand All @@ -339,7 +337,7 @@ export function map<T, U>(array: readonly T[] | undefined, f: (x: T, i: number)
let result: U[] | undefined;
if (array !== undefined) {
result = [];
for (let i = 0; i < array.length; i++) {
for (let i = 0, n = array.length; i < n; i++) {
result.push(f(array[i], i));
}
}
Expand Down Expand Up @@ -367,7 +365,7 @@ export function sameMap<T, U = T>(array: readonly T[] | undefined, f: (x: T, i:
/** @internal */
export function sameMap<T, U = T>(array: readonly T[] | undefined, f: (x: T, i: number) => U): readonly U[] | undefined {
if (array !== undefined) {
for (let i = 0; i < array.length; i++) {
for (let i = 0, n = array.length; i < n; i++) {
const item = array[i];
const mapped = f(item, i);
if (item as unknown !== mapped) {
Expand All @@ -392,7 +390,7 @@ export function sameMap<T, U = T>(array: readonly T[] | undefined, f: (x: T, i:
*/
export function flatten<T>(array: T[][] | readonly (T | readonly T[] | undefined)[]): T[] {
const result = [];
for (let i = 0; i < array.length; i++) {
for (let i = 0, n = array.length; i < n; i++) {
const v = array[i];
if (v) {
if (isArray(v)) {
Expand All @@ -417,7 +415,7 @@ export function flatten<T>(array: T[][] | readonly (T | readonly T[] | undefined
export function flatMap<T, U>(array: readonly T[] | undefined, mapfn: (x: T, i: number) => U | readonly U[] | undefined): readonly U[] {
let result: U[] | undefined;
if (array !== undefined) {
for (let i = 0; i < array.length; i++) {
for (let i = 0, n = array.length; i < n; i++) {
const v = mapfn(array[i], i);
if (v) {
if (isArray(v)) {
Expand All @@ -436,7 +434,7 @@ export function flatMap<T, U>(array: readonly T[] | undefined, mapfn: (x: T, i:
export function flatMapToMutable<T, U>(array: readonly T[] | undefined, mapfn: (x: T, i: number) => U | readonly U[] | undefined): U[] {
const result: U[] = [];
if (array !== undefined) {
for (let i = 0; i < array.length; i++) {
for (let i = 0, n = array.length; i < n; i++) {
const v = mapfn(array[i], i);
if (v) {
if (isArray(v)) {
Expand Down Expand Up @@ -476,7 +474,7 @@ export function sameFlatMap<T>(array: readonly T[], mapfn: (x: T, i: number) =>
export function sameFlatMap<T>(array: readonly T[], mapfn: (x: T, i: number) => T | readonly T[]): readonly T[] {
let result: T[] | undefined;
if (array !== undefined) {
for (let i = 0; i < array.length; i++) {
for (let i = 0, n = array.length; i < n; i++) {
const item = array[i];
const mapped = mapfn(item, i);
if (result || item !== mapped || isArray(mapped)) {
Expand All @@ -498,7 +496,7 @@ export function sameFlatMap<T>(array: readonly T[], mapfn: (x: T, i: number) =>
/** @internal */
export function mapAllOrFail<T, U>(array: readonly T[], mapFn: (x: T, i: number) => U | undefined): U[] | undefined {
const result: U[] = [];
for (let i = 0; i < array.length; i++) {
for (let i = 0, n = array.length; i < n; i++) {
const mapped = mapFn(array[i], i);
if (mapped === undefined) {
return undefined;
Expand All @@ -512,7 +510,7 @@ export function mapAllOrFail<T, U>(array: readonly T[], mapFn: (x: T, i: number)
export function mapDefined<T, U>(array: readonly T[] | undefined, mapFn: (x: T, i: number) => U | undefined): U[] {
const result: U[] = [];
if (array !== undefined) {
for (let i = 0; i < array.length; i++) {
for (let i = 0, n = array.length; i < n; i++) {
const mapped = mapFn(array[i], i);
if (mapped !== undefined) {
result.push(mapped);
Expand Down Expand Up @@ -635,7 +633,7 @@ export function some<T>(array: readonly T[] | undefined, predicate: (value: T) =
export function some<T>(array: readonly T[] | undefined, predicate?: (value: T) => boolean): boolean {
if (array !== undefined) {
if (predicate !== undefined) {
for (let i = 0; i < array.length; i++) {
for (let i = 0, n = array.length; i < n; i++) {
if (predicate(array[i])) {
return true;
}
Expand All @@ -655,7 +653,7 @@ export function some<T>(array: readonly T[] | undefined, predicate?: (value: T)
*/
export function getRangesWhere<T>(arr: readonly T[], pred: (t: T) => boolean, cb: (start: number, afterEnd: number) => void): void {
let start: number | undefined;
for (let i = 0; i < arr.length; i++) {
for (let i = 0, n = arr.length; i < n; i++) {
if (pred(arr[i])) {
start = start === undefined ? i : start;
}
Expand Down Expand Up @@ -725,7 +723,7 @@ function deduplicateRelational<T>(array: readonly T[], equalityComparer: Equalit

function deduplicateEquality<T>(array: readonly T[], equalityComparer: EqualityComparer<T>) {
const result: T[] = [];
for (let i = 0; i < array.length; i++) {
for (let i = 0, n = array.length; i < n; i++) {
pushIfUnique(result, array[i], equalityComparer);
}
return result;
Expand Down Expand Up @@ -844,11 +842,12 @@ export function arrayIsEqualTo<T>(array1: readonly T[] | undefined, array2: read
return array1 === array2;
}

if (array1.length !== array2.length) {
const firstLength = array1.length;
if (firstLength !== array2.length) {
return false;
}

for (let i = 0; i < array1.length; i++) {
for (let i = 0; i < firstLength; i++) {
if (!equalityComparer(array1[i], array2[i], i)) {
return false;
}
Expand All @@ -874,7 +873,7 @@ export function compact<T>(array: readonly T[]): readonly T[]; // eslint-disable
export function compact<T>(array: readonly T[]): readonly T[] {
let result: T[] | undefined;
if (array !== undefined) {
for (let i = 0; i < array.length; i++) {
for (let i = 0, n = array.length; i < n; i++) {
const v = array[i];
// Either the result has been initialized (and is looking to collect truthy values separately),
// or we've hit our first falsy value and need to copy over the current stretch of truthy values.
Expand Down Expand Up @@ -1452,7 +1451,7 @@ export function arrayToMap<T, U>(array: readonly T[], makeKey: (value: T) => str
/** @internal */
export function arrayToMap<K, V1, V2>(array: readonly V1[], makeKey: (value: V1) => K | undefined, makeValue: (value: V1) => V1 | V2 = identity): Map<K, V1 | V2> {
const result = new Map<K, V1 | V2>();
for (let i = 0; i < array.length; i++) {
for (let i = 0, n = array.length; i < n; i++) {
const value = array[i];
const key = makeKey(value);
if (key !== undefined) result.set(key, makeValue(value));
Expand All @@ -1467,7 +1466,7 @@ export function arrayToNumericMap<T, U>(array: readonly T[], makeKey: (value: T)
/** @internal */
export function arrayToNumericMap<T, U>(array: readonly T[], makeKey: (value: T) => number, makeValue: (value: T) => T | U = identity): (T | U)[] {
const result: (T | U)[] = [];
for (let i = 0; i < array.length; i++) {
for (let i = 0, n = array.length; i < n; i++) {
const value = array[i];
result[makeKey(value)] = makeValue(value);
}
Expand All @@ -1481,7 +1480,7 @@ export function arrayToMultiMap<K, V, U>(values: readonly V[], makeKey: (value:
/** @internal */
export function arrayToMultiMap<K, V, U>(values: readonly V[], makeKey: (value: V) => K, makeValue: (value: V) => V | U = identity): MultiMap<K, V | U> {
const result = createMultiMap<K, V | U>();
for (let i = 0; i < values.length; i++) {
for (let i = 0, n = values.length; i < n; i++) {
const value = values[i];
result.add(makeKey(value), makeValue(value));
}
Expand All @@ -1508,7 +1507,7 @@ export function groupBy<T, K extends string | number | boolean | null | undefine
export function groupBy<T, K extends string | number | boolean | null | undefined>(values: readonly T[] | undefined, keySelector: (value: T) => K): { [P in K as `${P}`]?: T[]; } { // eslint-disable-line no-restricted-syntax
const result: Record<string, T[]> = {};
if (values !== undefined) {
for (let i = 0; i < values.length; i++) {
for (let i = 0, n = values.length; i < n; i++) {
const value = values[i];
const key = `${keySelector(value)}`;
const array = result[key] ??= [];
Expand Down Expand Up @@ -1717,7 +1716,7 @@ export function createSet<TElement, THash = number>(getHashCode: (element: TElem
if (!multiMap.has(hash)) return false;
const candidates = multiMap.get(hash)!;
if (isArray(candidates)) {
for (let i = 0; i < candidates.length; i++) {
for (let i = 0, n = candidates.length; i < n; i++) {
if (equals(candidates[i], element)) {
if (candidates.length === 1) {
multiMap.delete(hash);
Expand Down Expand Up @@ -2122,7 +2121,7 @@ export function compareTextSpans(a: Partial<TextSpan> | undefined, b: Partial<Te

/** @internal */
export function maxBy<T>(arr: readonly T[], init: number, mapper: (x: T) => number): number {
for (let i = 0; i < arr.length; i++) {
for (let i = 0, n = arr.length; i < n; i++) {
init = Math.max(init, mapper(arr[i]));
}
return init;
Expand Down Expand Up @@ -2318,8 +2317,8 @@ export function getSpellingSuggestion<T>(name: string, candidates: Iterable<T>,
}

function levenshteinWithMax(s1: string, s2: string, max: number): number | undefined {
let previous = new Array(s2.length + 1);
let current = new Array(s2.length + 1);
let previous = new Array<number>(s2.length + 1);
let current = new Array<number>(s2.length + 1);
/** Represents any value > max. We don't care about the particular value. */
const big = max + 0.01;

Expand Down Expand Up @@ -2445,7 +2444,7 @@ export function removeMinAndVersionNumbers(fileName: string) {
* @internal
*/
export function orderedRemoveItem<T>(array: T[], item: T): boolean {
for (let i = 0; i < array.length; i++) {
for (let i = 0, n = array.length; i < n; i++) {
if (array[i] === item) {
orderedRemoveItemAt(array, i);
return true;
Expand Down Expand Up @@ -2485,7 +2484,7 @@ export function unorderedRemoveItem<T>(array: T[], item: T) {

/** Remove the *first* element satisfying `predicate`. */
function unorderedRemoveFirstItemWhere<T>(array: T[], predicate: (element: T) => boolean) {
for (let i = 0; i < array.length; i++) {
for (let i = 0, n = array.length; i < n; i++) {
if (predicate(array[i])) {
unorderedRemoveItemAt(array, i);
return true;
Expand Down Expand Up @@ -2537,7 +2536,7 @@ export function findBestPatternMatch<T>(values: readonly T[], getPattern: (value
// use length of prefix as betterness criteria
let longestMatchPrefixLength = -1;

for (let i = 0; i < values.length; i++) {
for (let i = 0, n = values.length; i < n; i++) {
const v = values[i];
const pattern = getPattern(v);
if (isPatternMatch(pattern, candidate) && pattern.prefix.length > longestMatchPrefixLength) {
Expand Down