129 lines
3.1 KiB
JavaScript
129 lines
3.1 KiB
JavaScript
/**
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* Copyright (c) 2013-present, Facebook, Inc.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*
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* @providesModule String.prototype.es6
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* @polyfill
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* @nolint
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*/
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/* eslint-disable no-extend-native, no-bitwise */
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/*
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* NOTE: We use (Number(x) || 0) to replace NaN values with zero.
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*/
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if (!String.prototype.startsWith) {
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String.prototype.startsWith = function(search) {
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'use strict';
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if (this == null) {
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throw TypeError();
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}
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var string = String(this);
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var pos = arguments.length > 1 ?
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(Number(arguments[1]) || 0) : 0;
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var start = Math.min(Math.max(pos, 0), string.length);
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return string.indexOf(String(search), pos) === start;
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};
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}
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if (!String.prototype.endsWith) {
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String.prototype.endsWith = function(search) {
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'use strict';
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if (this == null) {
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throw TypeError();
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}
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var string = String(this);
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var stringLength = string.length;
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var searchString = String(search);
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var pos = arguments.length > 1 ?
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(Number(arguments[1]) || 0) : stringLength;
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var end = Math.min(Math.max(pos, 0), stringLength);
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var start = end - searchString.length;
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if (start < 0) {
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return false;
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}
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return string.lastIndexOf(searchString, start) === start;
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};
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}
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if (!String.prototype.repeat) {
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String.prototype.repeat = function(count) {
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'use strict';
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if (this == null) {
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throw TypeError();
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}
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var string = String(this);
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count = Number(count) || 0;
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if (count < 0 || count === Infinity) {
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throw RangeError();
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}
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if (count === 1) {
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return string;
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}
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var result = '';
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while (count) {
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if (count & 1) {
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result += string;
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}
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if ((count >>= 1)) {
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string += string;
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}
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}
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return result;
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};
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}
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if (!String.prototype.includes) {
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String.prototype.includes = function(search, start) {
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'use strict';
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if (typeof start !== 'number') {
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start = 0;
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}
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if (start + search.length > this.length) {
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return false;
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} else {
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return this.indexOf(search, start) !== -1;
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}
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};
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}
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if (!String.prototype.codePointAt) {
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String.prototype.codePointAt = function(position) {
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if (this == null) {
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throw TypeError();
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}
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var string = String(this);
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var size = string.length;
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// `ToInteger`
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var index = position ? Number(position) : 0;
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if (Number.isNaN(index)) {
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index = 0;
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}
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// Account for out-of-bounds indices:
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if (index < 0 || index >= size) {
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return undefined;
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}
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// Get the first code unit
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var first = string.charCodeAt(index);
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var second;
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if (
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// check if it’s the start of a surrogate pair
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first >= 0xd800 &&
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first <= 0xdbff && // high surrogate
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size > index + 1 // there is a next code unit
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) {
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second = string.charCodeAt(index + 1);
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if (second >= 0xdc00 && second <= 0xdfff) {
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// low surrogate
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// http://mathiasbynens.be/notes/javascript-encoding#surrogate-formulae
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return (first - 0xd800) * 0x400 + second - 0xdc00 + 0x10000;
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}
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}
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return first;
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};
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}
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