| /* eslint-disable babel/new-cap, xo/throw-new-error */ |
| 'use strict'; |
| module.exports = function (str, pos) { |
| if (str === null || str === undefined) { |
| throw TypeError(); |
| } |
| |
| str = String(str); |
| |
| var size = str.length; |
| var i = pos ? Number(pos) : 0; |
| |
| if (Number.isNaN(i)) { |
| i = 0; |
| } |
| |
| if (i < 0 || i >= size) { |
| return undefined; |
| } |
| |
| var first = str.charCodeAt(i); |
| |
| if (first >= 0xD800 && first <= 0xDBFF && size > i + 1) { |
| var second = str.charCodeAt(i + 1); |
| |
| if (second >= 0xDC00 && second <= 0xDFFF) { |
| return ((first - 0xD800) * 0x400) + second - 0xDC00 + 0x10000; |
| } |
| } |
| |
| return first; |
| }; |