cubb
Version:
cubb是一种命令行的文本标记语言, 用于输出更友好的命令行文本。
45 lines • 1.71 kB
JavaScript
/*! http://mths.be/codepointat v0.1.0 by @mathias */
if (!String.prototype.codePointAt) {
(function() {
'use strict'; // 严格模式，needed to support `apply`/`call` with `undefined`/`null`
var codePointAt = function(position) {
if (this == null) {
throw TypeError();
}
var string = String(this);
var size = string.length;
// 变成整数
var index = position ? Number(position) : 0;
if (index != index) { // better `isNaN`
index = 0;
}
// 边界
if (index < 0 || index >= size) {
return undefined;
}
// 第一个编码单元
var first = string.charCodeAt(index);
var second;
if ( // 检查是否开始 surrogate pair
first >= 0xD800 && first <= 0xDBFF && // high surrogate
size > index + 1 // 下一个编码单元
) {
second = string.charCodeAt(index + 1);
if (second >= 0xDC00 && second <= 0xDFFF) { // low surrogate
// http://mathiasbynens.be/notes/javascript-encoding#surrogate-formulae
return (first - 0xD800) * 0x400 + second - 0xDC00 + 0x10000;
}
}
return first;
};
if (Object.defineProperty) {
Object.defineProperty(String.prototype, 'codePointAt', {
'value': codePointAt,
'configurable': true,
'writable': true
});
} else {
String.prototype.codePointAt = codePointAt;
}
}());
}