64 lines
1.8 KiB
JavaScript
64 lines
1.8 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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export function startsWith(haystack, needle) {
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if (haystack.length < needle.length) {
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return false;
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}
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for (let i = 0; i < needle.length; i++) {
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if (haystack[i] !== needle[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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/**
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* Determines if haystack ends with needle.
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*/
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export function endsWith(haystack, needle) {
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const diff = haystack.length - needle.length;
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if (diff > 0) {
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return haystack.lastIndexOf(needle) === diff;
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}
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else if (diff === 0) {
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return haystack === needle;
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}
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else {
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return false;
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}
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}
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/**
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* @returns the length of the common prefix of the two strings.
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*/
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export function commonPrefixLength(a, b) {
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let i;
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const len = Math.min(a.length, b.length);
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for (i = 0; i < len; i++) {
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if (a.charCodeAt(i) !== b.charCodeAt(i)) {
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return i;
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}
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}
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return len;
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}
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export function repeat(value, count) {
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let s = '';
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while (count > 0) {
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if ((count & 1) === 1) {
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s += value;
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}
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value += value;
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count = count >>> 1;
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}
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return s;
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}
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const _a = 'a'.charCodeAt(0);
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const _z = 'z'.charCodeAt(0);
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const _A = 'A'.charCodeAt(0);
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const _Z = 'Z'.charCodeAt(0);
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const _0 = '0'.charCodeAt(0);
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const _9 = '9'.charCodeAt(0);
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export function isLetterOrDigit(text, index) {
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const c = text.charCodeAt(index);
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return (_a <= c && c <= _z) || (_A <= c && c <= _Z) || (_0 <= c && c <= _9);
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}
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