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82 lines
2.7 KiB
JavaScript
82 lines
2.7 KiB
JavaScript
/*---------------------------------------------------------------------------------------------
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* Copyright (c) Microsoft Corporation. All rights reserved.
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* Licensed under the MIT License. See License.txt in the project root for license information.
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*--------------------------------------------------------------------------------------------*/
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import * as arrays from './arrays.js';
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/**
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* Compares two items for equality using strict equality.
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*/
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export const strictEquals = (a, b) => a === b;
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/**
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* Checks if the items of two arrays are equal.
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* By default, strict equality is used to compare elements, but a custom equality comparer can be provided.
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*/
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export function itemsEquals(itemEquals = strictEquals) {
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return (a, b) => arrays.equals(a, b, itemEquals);
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}
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/**
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* Uses `item.equals(other)` to determine equality.
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*/
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export function itemEquals() {
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return (a, b) => a.equals(b);
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}
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export function equalsIfDefined(equalsOrV1, v2, equals) {
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if (equals !== undefined) {
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const v1 = equalsOrV1;
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if (v1 === undefined || v1 === null || v2 === undefined || v2 === null) {
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return v2 === v1;
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}
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return equals(v1, v2);
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}
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else {
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const equals = equalsOrV1;
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return (v1, v2) => {
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if (v1 === undefined || v1 === null || v2 === undefined || v2 === null) {
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return v2 === v1;
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}
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return equals(v1, v2);
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};
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}
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}
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/**
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* Drills into arrays (items ordered) and objects (keys unordered) and uses strict equality on everything else.
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*/
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export function structuralEquals(a, b) {
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if (a === b) {
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return true;
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}
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if (Array.isArray(a) && Array.isArray(b)) {
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if (a.length !== b.length) {
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return false;
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}
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for (let i = 0; i < a.length; i++) {
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if (!structuralEquals(a[i], b[i])) {
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return false;
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}
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}
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return true;
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}
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if (a && typeof a === 'object' && b && typeof b === 'object') {
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if (Object.getPrototypeOf(a) === Object.prototype && Object.getPrototypeOf(b) === Object.prototype) {
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const aObj = a;
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const bObj = b;
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const keysA = Object.keys(aObj);
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const keysB = Object.keys(bObj);
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const keysBSet = new Set(keysB);
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if (keysA.length !== keysB.length) {
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return false;
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}
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for (const key of keysA) {
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if (!keysBSet.has(key)) {
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return false;
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}
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if (!structuralEquals(aObj[key], bObj[key])) {
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return false;
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}
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}
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return true;
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}
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}
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return false;
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}
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const objIds = new WeakMap();
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