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- /*! https://mths.be/codepointat v0.2.0 by @mathias */
- if (!String.prototype.codePointAt) {
- (function() {
- 'use strict'; // needed to support `apply`/`call` with `undefined`/`null`
- var defineProperty = (function() {
- // IE 8 only supports `Object.defineProperty` on DOM elements
- try {
- var object = {};
- var $defineProperty = Object.defineProperty;
- var result = $defineProperty(object, object, object) && $defineProperty;
- } catch(error) {}
- return result;
- }());
- var codePointAt = function(position) {
- if (this == null) {
- throw TypeError();
- }
- var string = String(this);
- var size = string.length;
- // `ToInteger`
- var index = position ? Number(position) : 0;
- if (index != index) { // better `isNaN`
- index = 0;
- }
- // Account for out-of-bounds indices:
- if (index < 0 || index >= size) {
- return undefined;
- }
- // Get the first code unit
- var first = string.charCodeAt(index);
- var second;
- if ( // check if it’s the start of a surrogate pair
- first >= 0xD800 && first <= 0xDBFF && // high surrogate
- size > index + 1 // there is a next code unit
- ) {
- second = string.charCodeAt(index + 1);
- if (second >= 0xDC00 && second <= 0xDFFF) { // low surrogate
- // https://mathiasbynens.be/notes/javascript-encoding#surrogate-formulae
- return (first - 0xD800) * 0x400 + second - 0xDC00 + 0x10000;
- }
- }
- return first;
- };
- if (defineProperty) {
- defineProperty(String.prototype, 'codePointAt', {
- 'value': codePointAt,
- 'configurable': true,
- 'writable': true
- });
- } else {
- String.prototype.codePointAt = codePointAt;
- }
- }());
- }
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