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2593 lines (2366 loc) · 90.2 KB
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import {
CharacterCodes,
Comparer,
Comparison,
Debug,
EqualityComparer,
MapLike,
Queue,
SortedArray,
SortedReadonlyArray,
TextSpan,
} from "./_namespaces/ts.js";
/* eslint-disable @typescript-eslint/prefer-for-of */
/** @internal */
export const emptyArray: never[] = [] as never[];
/** @internal */
export const emptyMap: ReadonlyMap<never, never> = new Map<never, never>();
/** @internal */
export function length(array: readonly any[] | undefined): number {
return array !== undefined ? array.length : 0;
}
/**
* Iterates through 'array' by index and performs the callback on each element of array until the callback
* returns a truthy value, then returns that value.
* If no such value is found, the callback is applied to each element of array and undefined is returned.
*
* @internal
*/
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++) {
const result = callback(array[i], i);
if (result) {
return result;
}
}
}
return undefined;
}
/**
* Like `forEach`, but iterates in reverse order.
*
* @internal
*/
export function forEachRight<T, U>(array: readonly T[] | undefined, callback: (element: T, index: number) => U | undefined): U | undefined {
if (array !== undefined) {
for (let i = array.length - 1; i >= 0; i--) {
const result = callback(array[i], i);
if (result) {
return result;
}
}
}
return undefined;
}
/**
* Like `forEach`, but suitable for use with numbers and strings (which may be falsy).
*
* @internal
*/
export function firstDefined<T, U>(array: readonly T[] | undefined, callback: (element: T, index: number) => U | undefined): U | undefined {
if (array === undefined) {
return undefined;
}
for (let i = 0; i < array.length; i++) {
const result = callback(array[i], i);
if (result !== undefined) {
return result;
}
}
return undefined;
}
/** @internal */
export function firstDefinedIterator<T, U>(iter: Iterable<T>, callback: (element: T) => U | undefined): U | undefined {
for (const value of iter) {
const result = callback(value);
if (result !== undefined) {
return result;
}
}
return undefined;
}
/** @internal */
export function reduceLeftIterator<T, U>(iterator: Iterable<T> | undefined, f: (memo: U, value: T, i: number) => U, initial: U): U {
let result = initial;
if (iterator) {
let pos = 0;
for (const value of iterator) {
result = f(result, value, pos);
pos++;
}
}
return result;
}
/** @internal */
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++) {
result.push(callback(arrayA[i], arrayB[i], i));
}
return result;
}
/**
* Creates a new array with `element` interspersed in between each element of `input`
* if there is more than 1 value in `input`. Otherwise, returns the existing array.
*
* @internal
*/
export function intersperse<T>(input: T[], element: T): T[] {
if (input.length <= 1) {
return input;
}
const result: T[] = [];
for (let i = 0, n = input.length; i < n; i++) {
if (i !== 0) result.push(element);
result.push(input[i]);
}
return result;
}
/**
* Iterates through `array` by index and performs the callback on each element of array until the callback
* returns a falsey value, then returns false.
* If no such value is found, the callback is applied to each element of array and `true` is returned.
*
* @internal
*/
export function every<T, U extends T>(array: readonly T[], callback: (element: T, index: number) => element is U): array is readonly U[];
/** @internal */
export function every<T, U extends T>(array: readonly T[] | undefined, callback: (element: T, index: number) => element is U): array is readonly U[] | undefined;
/** @internal */
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++) {
if (!callback(array[i], i)) {
return false;
}
}
}
return true;
}
/**
* Works like Array.prototype.find, returning `undefined` if no element satisfying the predicate is found.
*
* @internal
*/
export function find<T, U extends T>(array: readonly T[] | undefined, predicate: (element: T, index: number) => element is U, startIndex?: number): U | undefined;
/** @internal */
export function find<T>(array: readonly T[] | undefined, predicate: (element: T, index: number) => boolean, startIndex?: number): T | undefined;
/** @internal */
export function find<T>(array: readonly T[] | undefined, predicate: (element: T, index: number) => boolean, startIndex?: number): T | undefined {
if (array === undefined) return undefined;
for (let i = startIndex ?? 0; i < array.length; i++) {
const value = array[i];
if (predicate(value, i)) {
return value;
}
}
return undefined;
}
/** @internal */
export function findLast<T, U extends T>(array: readonly T[] | undefined, predicate: (element: T, index: number) => element is U, startIndex?: number): U | undefined;
/** @internal */
export function findLast<T>(array: readonly T[] | undefined, predicate: (element: T, index: number) => boolean, startIndex?: number): T | undefined;
/** @internal */
export function findLast<T>(array: readonly T[] | undefined, predicate: (element: T, index: number) => boolean, startIndex?: number): T | undefined {
if (array === undefined) return undefined;
for (let i = startIndex ?? array.length - 1; i >= 0; i--) {
const value = array[i];
if (predicate(value, i)) {
return value;
}
}
return undefined;
}
/**
* Works like Array.prototype.findIndex, returning `-1` if no element satisfying the predicate is found.
*
* @internal
*/
export function findIndex<T>(array: readonly T[] | undefined, predicate: (element: T, index: number) => boolean, startIndex?: number): number {
if (array === undefined) return -1;
for (let i = startIndex ?? 0; i < array.length; i++) {
if (predicate(array[i], i)) {
return i;
}
}
return -1;
}
/** @internal */
export function findLastIndex<T>(array: readonly T[] | undefined, predicate: (element: T, index: number) => boolean, startIndex?: number): number {
if (array === undefined) return -1;
for (let i = startIndex ?? array.length - 1; i >= 0; i--) {
if (predicate(array[i], i)) {
return i;
}
}
return -1;
}
/** @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++) {
if (equalityComparer(array[i], value)) {
return true;
}
}
}
return false;
}
/** @internal */
export function indexOfAnyCharCode(text: string, charCodes: readonly number[], start?: number): number {
for (let i = start ?? 0; i < text.length; i++) {
if (contains(charCodes, text.charCodeAt(i))) {
return i;
}
}
return -1;
}
/** @internal */
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++) {
const v = array[i];
if (predicate(v, i)) {
count++;
}
}
}
return count;
}
/**
* Filters an array by a predicate function. Returns the same array instance if the predicate is
* true for all elements, otherwise returns a new array instance containing the filtered subset.
*
* @internal
*/
export function filter<T, U extends T>(array: T[], f: (x: T) => x is U): U[];
/** @internal */
export function filter<T>(array: T[], f: (x: T) => boolean): T[];
/** @internal */
export function filter<T, U extends T>(array: readonly T[], f: (x: T) => x is U): readonly U[];
/** @internal */
export function filter<T>(array: readonly T[], f: (x: T) => boolean): readonly T[];
/** @internal */
export function filter<T, U extends T>(array: T[] | undefined, f: (x: T) => x is U): U[] | undefined;
/** @internal */
export function filter<T>(array: T[] | undefined, f: (x: T) => boolean): T[] | undefined;
/** @internal */
export function filter<T, U extends T>(array: readonly T[] | undefined, f: (x: T) => x is U): readonly U[] | undefined;
/** @internal */
export function filter<T>(array: readonly T[] | undefined, f: (x: T) => boolean): readonly T[] | undefined;
/** @internal */
export function filter<T>(array: readonly T[] | undefined, f: (x: T) => boolean): readonly T[] | undefined {
if (array !== undefined) {
const len = array.length;
let i = 0;
while (i < len && f(array[i])) i++;
if (i < len) {
const result = array.slice(0, i);
i++;
while (i < len) {
const item = array[i];
if (f(item)) {
result.push(item);
}
i++;
}
return result;
}
}
return array;
}
/** @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++) {
if (f(array[i], i, array)) {
array[outIndex] = array[i];
outIndex++;
}
}
array.length = outIndex;
}
/** @internal */
export function clear(array: unknown[]): void {
array.length = 0;
}
/** @internal */
export function map<T, U>(array: readonly T[], f: (x: T, i: number) => U): U[];
/** @internal */
export function map<T, U>(array: readonly T[] | undefined, f: (x: T, i: number) => U): U[] | undefined;
/** @internal */
export function map<T, U>(array: readonly T[] | undefined, f: (x: T, i: number) => U): U[] | undefined {
let result: U[] | undefined;
if (array !== undefined) {
result = [];
for (let i = 0; i < array.length; i++) {
result.push(f(array[i], i));
}
}
return result;
}
/** @internal */
export function* mapIterator<T, U>(iter: Iterable<T>, mapFn: (x: T) => U): Generator<U, void, unknown> {
for (const x of iter) {
yield mapFn(x);
}
}
/**
* Maps from T to T and avoids allocation if all elements map to themselves
*
* @internal */
export function sameMap<T, U = T>(array: T[], f: (x: T, i: number) => U): U[];
/** @internal */
export function sameMap<T, U = T>(array: readonly T[], f: (x: T, i: number) => U): readonly U[];
/** @internal */
export function sameMap<T, U = T>(array: T[] | undefined, f: (x: T, i: number) => U): U[] | undefined;
/** @internal */
export function sameMap<T, U = T>(array: readonly T[] | undefined, f: (x: T, i: number) => U): readonly U[] | undefined;
/** @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++) {
const item = array[i];
const mapped = f(item, i);
if (item as unknown !== mapped) {
const result: U[] = array.slice(0, i) as unknown[] as U[];
result.push(mapped);
for (i++; i < array.length; i++) {
result.push(f(array[i], i));
}
return result;
}
}
}
return array as unknown[] as U[];
}
/**
* Flattens an array containing a mix of array or non-array elements.
*
* @param array The array to flatten.
*
* @internal
*/
export function flatten<T>(array: T[][] | readonly (T | readonly T[] | undefined)[]): T[] {
const result = [];
for (let i = 0; i < array.length; i++) {
const v = array[i];
if (v) {
if (isArray(v)) {
addRange(result, v);
}
else {
result.push(v);
}
}
}
return result;
}
/**
* Maps an array. If the mapped value is an array, it is spread into the result.
*
* @param array The array to map.
* @param mapfn The callback used to map the result into one or more values.
*
* @internal
*/
export function flatMap<T, U extends {}>(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++) {
const v = mapfn(array[i], i);
if (v) {
if (isArray(v)) {
result = addRange(result, v);
}
else {
result = append(result, v);
}
}
}
}
return result ?? emptyArray;
}
/** @internal */
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++) {
const v = mapfn(array[i], i);
if (v) {
if (isArray(v)) {
addRange(result, v);
}
else {
result.push(v);
}
}
}
}
return result;
}
/** @internal */
export function* flatMapIterator<T, U>(iter: Iterable<T>, mapfn: (x: T) => readonly U[] | Iterable<U> | undefined): Generator<U, void, any> {
for (const x of iter) {
const iter2 = mapfn(x);
if (!iter2) continue;
yield* iter2;
}
}
/**
* Maps an array. If the mapped value is an array, it is spread into the result.
* Avoids allocation if all elements map to themselves.
*
* @param array The array to map.
* @param mapfn The callback used to map the result into one or more values.
*
* @internal
*/
export function sameFlatMap<T>(array: T[], mapfn: (x: T, i: number) => T | readonly T[]): T[];
/** @internal */
export function sameFlatMap<T>(array: readonly T[], mapfn: (x: T, i: number) => T | readonly T[]): readonly T[];
/** @internal */
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++) {
const item = array[i];
const mapped = mapfn(item, i);
if (result || item !== mapped || isArray(mapped)) {
if (!result) {
result = array.slice(0, i);
}
if (isArray(mapped)) {
addRange(result, mapped);
}
else {
result.push(mapped);
}
}
}
}
return result ?? array;
}
/** @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++) {
const mapped = mapFn(array[i], i);
if (mapped === undefined) {
return undefined;
}
result.push(mapped);
}
return result;
}
/** @internal */
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++) {
const mapped = mapFn(array[i], i);
if (mapped !== undefined) {
result.push(mapped);
}
}
}
return result;
}
/** @internal */
// eslint-disable-next-line no-restricted-syntax
export function* mapDefinedIterator<T, U>(iter: Iterable<T>, mapFn: (x: T) => U | undefined): Generator<U & ({} | null), void, unknown> {
for (const x of iter) {
const value = mapFn(x);
if (value !== undefined) {
yield value;
}
}
}
/** @internal */
export function getOrUpdate<K, V>(map: Map<K, V>, key: K, callback: () => V): V {
if (map.has(key)) {
return map.get(key)!;
}
const value = callback();
map.set(key, value);
return value;
}
/** @internal */
export function tryAddToSet<T>(set: Set<T>, value: T): boolean {
if (!set.has(value)) {
set.add(value);
return true;
}
return false;
}
/** @internal */
export function* singleIterator<T>(value: T): Generator<T, void, unknown> {
yield value;
}
/**
* Maps contiguous spans of values with the same key.
*
* @param array The array to map.
* @param keyfn A callback used to select the key for an element.
* @param mapfn A callback used to map a contiguous chunk of values to a single value.
*
* @internal
*/
export function spanMap<T, K, U>(array: readonly T[], keyfn: (x: T, i: number) => K, mapfn: (chunk: T[], key: K, start: number, end: number) => U): U[];
/** @internal */
export function spanMap<T, K, U>(array: readonly T[] | undefined, keyfn: (x: T, i: number) => K, mapfn: (chunk: T[], key: K, start: number, end: number) => U): U[] | undefined;
/** @internal */
export function spanMap<T, K, U>(array: readonly T[] | undefined, keyfn: (x: T, i: number) => K, mapfn: (chunk: T[], key: K, start: number, end: number) => U): U[] | undefined {
let result: U[] | undefined;
if (array !== undefined) {
result = [];
const len = array.length;
let previousKey: K | undefined;
let key: K | undefined;
let start = 0;
let pos = 0;
while (start < len) {
while (pos < len) {
const value = array[pos];
key = keyfn(value, pos);
if (pos === 0) {
previousKey = key;
}
else if (key !== previousKey) {
break;
}
pos++;
}
if (start < pos) {
const v = mapfn(array.slice(start, pos), previousKey!, start, pos);
if (v) {
result.push(v);
}
start = pos;
}
previousKey = key;
pos++;
}
}
return result;
}
/** @internal */
export function mapEntries<K1, V1, K2, V2>(map: ReadonlyMap<K1, V1>, f: (key: K1, value: V1) => readonly [K2, V2]): Map<K2, V2>;
/** @internal */
export function mapEntries<K1, V1, K2, V2>(map: ReadonlyMap<K1, V1> | undefined, f: (key: K1, value: V1) => readonly [K2, V2]): Map<K2, V2> | undefined;
/** @internal */
export function mapEntries<K1, V1, K2, V2>(map: ReadonlyMap<K1, V1> | undefined, f: (key: K1, value: V1) => readonly [K2, V2]): Map<K2, V2> | undefined {
if (map === undefined) {
return undefined;
}
const result = new Map<K2, V2>();
map.forEach((value, key) => {
const [newKey, newValue] = f(key, value);
result.set(newKey, newValue);
});
return result;
}
/** @internal */
export function some<T>(array: readonly T[] | undefined): array is readonly T[];
/** @internal */
export function some<T>(array: readonly T[] | undefined, predicate: (value: T) => boolean): boolean;
/** @internal */
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++) {
if (predicate(array[i])) {
return true;
}
}
}
else {
return array.length > 0;
}
}
return false;
}
/**
* Calls the callback with (start, afterEnd) index pairs for each range where 'pred' is true.
*
* @internal
*/
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++) {
if (pred(arr[i])) {
start = start === undefined ? i : start;
}
else {
if (start !== undefined) {
cb(start, i);
start = undefined;
}
}
}
if (start !== undefined) cb(start, arr.length);
}
/** @internal */
export function concatenate<T>(array1: T[], array2: T[]): T[];
/** @internal */
export function concatenate<T>(array1: readonly T[], array2: readonly T[]): readonly T[];
/** @internal */
export function concatenate<T>(array1: T[], array2: T[] | undefined): T[]; // eslint-disable-line @typescript-eslint/unified-signatures
/** @internal */
export function concatenate<T>(array1: T[] | undefined, array2: T[]): T[]; // eslint-disable-line @typescript-eslint/unified-signatures
/** @internal */
export function concatenate<T>(array1: readonly T[], array2: readonly T[] | undefined): readonly T[]; // eslint-disable-line @typescript-eslint/unified-signatures
/** @internal */
export function concatenate<T>(array1: readonly T[] | undefined, array2: readonly T[]): readonly T[]; // eslint-disable-line @typescript-eslint/unified-signatures
/** @internal */
export function concatenate<T>(array1: T[] | undefined, array2: T[] | undefined): T[] | undefined;
/** @internal */
export function concatenate<T>(array1: readonly T[] | undefined, array2: readonly T[] | undefined): readonly T[] | undefined;
/** @internal */
export function concatenate<T>(array1: readonly T[] | undefined, array2: readonly T[] | undefined): readonly T[] | undefined {
if (array2 === undefined || array2.length === 0) return array1;
if (array1 === undefined || array1.length === 0) return array2;
return [...array1, ...array2];
}
function selectIndex(_: unknown, i: number) {
return i;
}
/** @internal */
export function indicesOf(array: readonly unknown[]): number[] {
return array.map(selectIndex);
}
function deduplicateRelational<T>(array: readonly T[], equalityComparer: EqualityComparer<T>, comparer: Comparer<T>) {
// Perform a stable sort of the array. This ensures the first entry in a list of
// duplicates remains the first entry in the result.
const indices = indicesOf(array);
stableSortIndices(array, indices, comparer);
let last = array[indices[0]];
const deduplicated: number[] = [indices[0]];
for (let i = 1; i < indices.length; i++) {
const index = indices[i];
const item = array[index];
if (!equalityComparer(last, item)) {
deduplicated.push(index);
last = item;
}
}
// restore original order
deduplicated.sort();
return deduplicated.map(i => array[i]);
}
function deduplicateEquality<T>(array: readonly T[], equalityComparer: EqualityComparer<T>) {
const result: T[] = [];
for (let i = 0; i < array.length; i++) {
pushIfUnique(result, array[i], equalityComparer);
}
return result;
}
/**
* Deduplicates an unsorted array.
* @param equalityComparer An `EqualityComparer` used to determine if two values are duplicates.
* @param comparer An optional `Comparer` used to sort entries before comparison, though the
* result will remain in the original order in `array`.
*
* @internal
*/
export function deduplicate<T>(array: readonly T[], equalityComparer: EqualityComparer<T>, comparer?: Comparer<T>): T[] {
return array.length === 0 ? [] :
array.length === 1 ? array.slice() :
comparer ? deduplicateRelational(array, equalityComparer, comparer) :
deduplicateEquality(array, equalityComparer);
}
/**
* Deduplicates an array that has already been sorted.
*/
function deduplicateSorted<T>(array: SortedReadonlyArray<T>, comparer: EqualityComparer<T> | Comparer<T>): SortedReadonlyArray<T> {
if (array.length === 0) return emptyArray as any as SortedReadonlyArray<T>;
let last = array[0];
const deduplicated: T[] = [last];
for (let i = 1; i < array.length; i++) {
const next = array[i];
switch (comparer(next, last)) {
// equality comparison
case true:
// relational comparison
// falls through
case Comparison.EqualTo:
continue;
case Comparison.LessThan:
// If `array` is sorted, `next` should **never** be less than `last`.
return Debug.fail("Array is unsorted.");
}
deduplicated.push(last = next);
}
return deduplicated as any as SortedReadonlyArray<T>;
}
/** @internal */
export function createSortedArray<T>(): SortedArray<T> {
return [] as any as SortedArray<T>; // TODO: GH#19873
}
/** @internal */
export function insertSorted<T>(
array: SortedArray<T>,
insert: T,
compare: Comparer<T>,
equalityComparer?: EqualityComparer<T>,
allowDuplicates?: boolean,
): boolean {
if (array.length === 0) {
array.push(insert);
return true;
}
const insertIndex = binarySearch(array, insert, identity, compare);
if (insertIndex < 0) {
if (equalityComparer && !allowDuplicates) {
const idx = ~insertIndex;
if (idx > 0 && equalityComparer(insert, array[idx - 1])) {
return false;
}
if (idx < array.length && equalityComparer(insert, array[idx])) {
array.splice(idx, 1, insert);
return true;
}
}
array.splice(~insertIndex, 0, insert);
return true;
}
if (allowDuplicates) {
array.splice(insertIndex, 0, insert);
return true;
}
return false;
}
/** @internal */
export function sortAndDeduplicate(array: readonly string[]): SortedReadonlyArray<string>;
/** @internal */
export function sortAndDeduplicate<T>(array: readonly T[], comparer: Comparer<T>, equalityComparer?: EqualityComparer<T>): SortedReadonlyArray<T>;
/** @internal */
export function sortAndDeduplicate<T>(array: readonly T[], comparer?: Comparer<T>, equalityComparer?: EqualityComparer<T>): SortedReadonlyArray<T> {
return deduplicateSorted(toSorted(array, comparer), equalityComparer ?? comparer ?? compareStringsCaseSensitive as any as Comparer<T>);
}
/** @internal */
export function arrayIsEqualTo<T>(array1: readonly T[] | undefined, array2: readonly T[] | undefined, equalityComparer: (a: T, b: T, index: number) => boolean = equateValues): boolean {
if (array1 === undefined || array2 === undefined) {
return array1 === array2;
}
if (array1.length !== array2.length) {
return false;
}
for (let i = 0; i < array1.length; i++) {
if (!equalityComparer(array1[i], array2[i], i)) {
return false;
}
}
return true;
}
/**
* Compacts an array, removing any falsey elements.
*
* @internal
*/
export function compact<T>(array: (T | undefined | null | false | 0 | "")[]): T[]; // eslint-disable-line no-restricted-syntax
/** @internal */
export function compact<T>(array: readonly (T | undefined | null | false | 0 | "")[]): readonly T[]; // eslint-disable-line no-restricted-syntax
// ESLint thinks these can be combined with the above - they cannot; they'd produce higher-priority inferences and prevent the falsey types from being stripped
/** @internal */
export function compact<T>(array: T[]): T[]; // eslint-disable-line @typescript-eslint/unified-signatures
/** @internal */
export function compact<T>(array: readonly T[]): readonly T[]; // eslint-disable-line @typescript-eslint/unified-signatures
/** @internal */
export function compact<T>(array: readonly T[]): readonly T[] {
let result: T[] | undefined;
if (array !== undefined) {
for (let i = 0; i < array.length; 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.
if (result ?? !v) {
result ??= array.slice(0, i);
if (v) {
result.push(v);
}
}
}
}
return result ?? array;
}
/**
* Gets the relative complement of `arrayA` with respect to `arrayB`, returning the elements that
* are not present in `arrayA` but are present in `arrayB`. Assumes both arrays are sorted
* based on the provided comparer.
*
* @internal
*/
export function relativeComplement<T>(arrayA: T[] | undefined, arrayB: T[] | undefined, comparer: Comparer<T>): T[] | undefined {
if (!arrayB || !arrayA || arrayB.length === 0 || arrayA.length === 0) return arrayB;
const result: T[] = [];
loopB:
for (let offsetA = 0, offsetB = 0; offsetB < arrayB.length; offsetB++) {
if (offsetB > 0) {
// Ensure `arrayB` is properly sorted.
Debug.assertGreaterThanOrEqual(comparer(arrayB[offsetB], arrayB[offsetB - 1]), Comparison.EqualTo);
}
loopA:
for (const startA = offsetA; offsetA < arrayA.length; offsetA++) {
if (offsetA > startA) {
// Ensure `arrayA` is properly sorted. We only need to perform this check if
// `offsetA` has changed since we entered the loop.
Debug.assertGreaterThanOrEqual(comparer(arrayA[offsetA], arrayA[offsetA - 1]), Comparison.EqualTo);
}
switch (comparer(arrayB[offsetB], arrayA[offsetA])) {
case Comparison.LessThan:
// If B is less than A, B does not exist in arrayA. Add B to the result and
// move to the next element in arrayB without changing the current position
// in arrayA.
result.push(arrayB[offsetB]);
continue loopB;
case Comparison.EqualTo:
// If B is equal to A, B exists in arrayA. Move to the next element in
// arrayB without adding B to the result or changing the current position
// in arrayA.
continue loopB;
case Comparison.GreaterThan:
// If B is greater than A, we need to keep looking for B in arrayA. Move to
// the next element in arrayA and recheck.
continue loopA;
}
}
}
return result;
}
/**
* Appends a value to an array, returning the array.
*
* @param to The array to which `value` is to be appended. If `to` is `undefined`, a new array
* is created if `value` was appended.
* @param value The value to append to the array. If `value` is `undefined`, nothing is
* appended.
*
* @internal
*/
export function append<T extends {}>(to: T[], value: T | undefined): T[];
/** @internal */
export function append<T extends {}>(to: T[] | undefined, value: T): T[];
/** @internal */
export function append<T extends {}>(to: T[] | undefined, value: T | undefined): T[] | undefined;
export function append<T extends {}>(to: T[] | undefined, value: T | undefined): T[] | undefined {
if (value === undefined) return to;
if (to === undefined) return [value];
to.push(value);
return to;
}
/**
* Combines two arrays, values, or undefineds into the smallest container that can accommodate the resulting set:
*
* ```
* undefined -> undefined -> undefined
* T -> undefined -> T
* T -> T -> T[]
* T[] -> undefined -> T[] (no-op)
* T[] -> T -> T[] (append)
* T[] -> T[] -> T[] (concatenate)
* ```
*
* @internal
*/
export function combine<T extends {}>(xs: T[] | undefined, ys: T[] | undefined): T[] | undefined;
/** @internal */
export function combine<T extends {}>(xs: T | readonly T[] | undefined, ys: T | readonly T[] | undefined): T | readonly T[] | undefined;
/** @internal */
export function combine<T extends {}>(xs: T | T[] | undefined, ys: T | T[] | undefined): T | T[] | undefined;
/** @internal */
export function combine<T extends {}>(xs: T | T[] | undefined, ys: T | T[] | undefined) {
if (xs === undefined) return ys;
if (ys === undefined) return xs;
if (isArray(xs)) return isArray(ys) ? concatenate(xs, ys) : append(xs, ys);
if (isArray(ys)) return append(ys, xs);
return [xs, ys];
}
/**
* Gets the actual offset into an array for a relative offset. Negative offsets indicate a
* position offset from the end of the array.
*/
function toOffset(array: readonly any[], offset: number) {
return offset < 0 ? array.length + offset : offset;
}
/**
* Appends a range of value to an array, returning the array.
*
* @param to The array to which `value` is to be appended. If `to` is `undefined`, a new array
* is created if `value` was appended.
* @param from The values to append to the array. If `from` is `undefined`, nothing is
* appended. If an element of `from` is `undefined`, that element is not appended.
* @param start The offset in `from` at which to start copying values.
* @param end The offset in `from` at which to stop copying values (non-inclusive).
*
* @internal
*/
export function addRange<T>(to: T[], from: readonly T[] | undefined, start?: number, end?: number): T[];
/** @internal */
export function addRange<T>(to: T[] | undefined, from: readonly T[] | undefined, start?: number, end?: number): T[] | undefined;
/** @internal */
export function addRange<T>(to: T[] | undefined, from: readonly T[] | undefined, start?: number, end?: number): T[] | undefined {
if (from === undefined || from.length === 0) return to;
if (to === undefined) return from.slice(start, end);
start = start === undefined ? 0 : toOffset(from, start);
end = end === undefined ? from.length : toOffset(from, end);
for (let i = start; i < end && i < from.length; i++) {
if (from[i] !== undefined) {
to.push(from[i]);
}
}
return to;
}
/**
* @return Whether the value was added.
*