/
String.prototype.es6.js
92 lines (85 loc) · 2.21 KB
/
String.prototype.es6.js
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/**
* Copyright (c) 2013-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*
* @polyfill
*/
/* eslint-disable strict, no-extend-native, no-bitwise */
/*
* NOTE: We use (Number(x) || 0) to replace NaN values with zero.
*/
if (!String.prototype.startsWith) {
String.prototype.startsWith = function(search) {
'use strict';
if (this == null) {
throw TypeError();
}
var string = String(this);
var pos = arguments.length > 1 ?
(Number(arguments[1]) || 0) : 0;
var start = Math.min(Math.max(pos, 0), string.length);
return string.indexOf(String(search), pos) === start;
};
}
if (!String.prototype.endsWith) {
String.prototype.endsWith = function(search) {
'use strict';
if (this == null) {
throw TypeError();
}
var string = String(this);
var stringLength = string.length;
var searchString = String(search);
var pos = arguments.length > 1 ?
(Number(arguments[1]) || 0) : stringLength;
var end = Math.min(Math.max(pos, 0), stringLength);
var start = end - searchString.length;
if (start < 0) {
return false;
}
return string.lastIndexOf(searchString, start) === start;
};
}
if (!String.prototype.repeat) {
String.prototype.repeat = function(count) {
'use strict';
if (this == null) {
throw TypeError();
}
var string = String(this);
count = Number(count) || 0;
if (count < 0 || count === Infinity) {
throw RangeError();
}
if (count === 1) {
return string;
}
var result = '';
while (count) {
if (count & 1) {
result += string;
}
if ((count >>= 1)) {
string += string;
}
}
return result;
};
}
if (!String.prototype.includes) {
String.prototype.includes = function(search, start) {
'use strict';
if (typeof start !== 'number') {
start = 0;
}
if (start + search.length > this.length) {
return false;
} else {
return this.indexOf(search, start) !== -1;
}
};
}