59 lines
1.8 KiB
TypeScript
59 lines
1.8 KiB
TypeScript
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/*---------------------------------------------------------------------------------------------
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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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/**
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* Return a hash value for an object.
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*/
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export function hash(obj: any, hashVal = 0): number {
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switch (typeof obj) {
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case 'object':
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if (obj === null) {
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return numberHash(349, hashVal);
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} else if (Array.isArray(obj)) {
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return arrayHash(obj, hashVal);
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}
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return objectHash(obj, hashVal);
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case 'string':
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return stringHash(obj, hashVal);
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case 'boolean':
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return booleanHash(obj, hashVal);
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case 'number':
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return numberHash(obj, hashVal);
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case 'undefined':
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return 937 * 31;
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default:
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return numberHash(obj, 617);
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}
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}
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function numberHash(val: number, initialHashVal: number): number {
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return (((initialHashVal << 5) - initialHashVal) + val) | 0; // hashVal * 31 + ch, keep as int32
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}
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function booleanHash(b: boolean, initialHashVal: number): number {
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return numberHash(b ? 433 : 863, initialHashVal);
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}
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function stringHash(s: string, hashVal: number) {
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hashVal = numberHash(149417, hashVal);
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for (let i = 0, length = s.length; i < length; i++) {
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hashVal = numberHash(s.charCodeAt(i), hashVal);
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}
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return hashVal;
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}
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function arrayHash(arr: any[], initialHashVal: number): number {
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initialHashVal = numberHash(104579, initialHashVal);
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return arr.reduce((hashVal, item) => hash(item, hashVal), initialHashVal);
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}
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function objectHash(obj: any, initialHashVal: number): number {
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initialHashVal = numberHash(181387, initialHashVal);
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return Object.keys(obj).sort().reduce((hashVal, key) => {
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hashVal = stringHash(key, hashVal);
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return hash(obj[key], hashVal);
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}, initialHashVal);
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}
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