neocities/public/js/monaco/esm/vs/base/common/arraysFind.js

175 lines
5.9 KiB
JavaScript

/*---------------------------------------------------------------------------------------------
* Copyright (c) Microsoft Corporation. All rights reserved.
* Licensed under the MIT License. See License.txt in the project root for license information.
*--------------------------------------------------------------------------------------------*/
export function findLast(array, predicate) {
const idx = findLastIdx(array, predicate);
if (idx === -1) {
return undefined;
}
return array[idx];
}
export function findLastIdx(array, predicate, fromIndex = array.length - 1) {
for (let i = fromIndex; i >= 0; i--) {
const element = array[i];
if (predicate(element)) {
return i;
}
}
return -1;
}
/**
* Finds the last item where predicate is true using binary search.
* `predicate` must be monotonous, i.e. `arr.map(predicate)` must be like `[true, ..., true, false, ..., false]`!
*
* @returns `undefined` if no item matches, otherwise the last item that matches the predicate.
*/
export function findLastMonotonous(array, predicate) {
const idx = findLastIdxMonotonous(array, predicate);
return idx === -1 ? undefined : array[idx];
}
/**
* Finds the last item where predicate is true using binary search.
* `predicate` must be monotonous, i.e. `arr.map(predicate)` must be like `[true, ..., true, false, ..., false]`!
*
* @returns `startIdx - 1` if predicate is false for all items, otherwise the index of the last item that matches the predicate.
*/
export function findLastIdxMonotonous(array, predicate, startIdx = 0, endIdxEx = array.length) {
let i = startIdx;
let j = endIdxEx;
while (i < j) {
const k = Math.floor((i + j) / 2);
if (predicate(array[k])) {
i = k + 1;
}
else {
j = k;
}
}
return i - 1;
}
/**
* Finds the first item where predicate is true using binary search.
* `predicate` must be monotonous, i.e. `arr.map(predicate)` must be like `[false, ..., false, true, ..., true]`!
*
* @returns `undefined` if no item matches, otherwise the first item that matches the predicate.
*/
export function findFirstMonotonous(array, predicate) {
const idx = findFirstIdxMonotonousOrArrLen(array, predicate);
return idx === array.length ? undefined : array[idx];
}
/**
* Finds the first item where predicate is true using binary search.
* `predicate` must be monotonous, i.e. `arr.map(predicate)` must be like `[false, ..., false, true, ..., true]`!
*
* @returns `endIdxEx` if predicate is false for all items, otherwise the index of the first item that matches the predicate.
*/
export function findFirstIdxMonotonousOrArrLen(array, predicate, startIdx = 0, endIdxEx = array.length) {
let i = startIdx;
let j = endIdxEx;
while (i < j) {
const k = Math.floor((i + j) / 2);
if (predicate(array[k])) {
j = k;
}
else {
i = k + 1;
}
}
return i;
}
/**
* Use this when
* * You have a sorted array
* * You query this array with a monotonous predicate to find the last item that has a certain property.
* * You query this array multiple times with monotonous predicates that get weaker and weaker.
*/
export class MonotonousArray {
static { this.assertInvariants = false; }
constructor(_array) {
this._array = _array;
this._findLastMonotonousLastIdx = 0;
}
/**
* The predicate must be monotonous, i.e. `arr.map(predicate)` must be like `[true, ..., true, false, ..., false]`!
* For subsequent calls, current predicate must be weaker than (or equal to) the previous predicate, i.e. more entries must be `true`.
*/
findLastMonotonous(predicate) {
if (MonotonousArray.assertInvariants) {
if (this._prevFindLastPredicate) {
for (const item of this._array) {
if (this._prevFindLastPredicate(item) && !predicate(item)) {
throw new Error('MonotonousArray: current predicate must be weaker than (or equal to) the previous predicate.');
}
}
}
this._prevFindLastPredicate = predicate;
}
const idx = findLastIdxMonotonous(this._array, predicate, this._findLastMonotonousLastIdx);
this._findLastMonotonousLastIdx = idx + 1;
return idx === -1 ? undefined : this._array[idx];
}
}
/**
* Returns the first item that is equal to or greater than every other item.
*/
export function findFirstMax(array, comparator) {
if (array.length === 0) {
return undefined;
}
let max = array[0];
for (let i = 1; i < array.length; i++) {
const item = array[i];
if (comparator(item, max) > 0) {
max = item;
}
}
return max;
}
/**
* Returns the last item that is equal to or greater than every other item.
*/
export function findLastMax(array, comparator) {
if (array.length === 0) {
return undefined;
}
let max = array[0];
for (let i = 1; i < array.length; i++) {
const item = array[i];
if (comparator(item, max) >= 0) {
max = item;
}
}
return max;
}
/**
* Returns the first item that is equal to or less than every other item.
*/
export function findFirstMin(array, comparator) {
return findFirstMax(array, (a, b) => -comparator(a, b));
}
export function findMaxIdx(array, comparator) {
if (array.length === 0) {
return -1;
}
let maxIdx = 0;
for (let i = 1; i < array.length; i++) {
const item = array[i];
if (comparator(item, array[maxIdx]) > 0) {
maxIdx = i;
}
}
return maxIdx;
}
/**
* Returns the first mapped value of the array which is not undefined.
*/
export function mapFindFirst(items, mapFn) {
for (const value of items) {
const mapped = mapFn(value);
if (mapped !== undefined) {
return mapped;
}
}
return undefined;
}