1/* eslint-disable babel/new-cap, xo/throw-new-error */ 2'use strict'; 3module.exports = function (str, pos) { 4 if (str === null || str === undefined) { 5 throw TypeError(); 6 } 7 8 str = String(str); 9 10 var size = str.length; 11 var i = pos ? Number(pos) : 0; 12 13 if (Number.isNaN(i)) { 14 i = 0; 15 } 16 17 if (i < 0 || i >= size) { 18 return undefined; 19 } 20 21 var first = str.charCodeAt(i); 22 23 if (first >= 0xD800 && first <= 0xDBFF && size > i + 1) { 24 var second = str.charCodeAt(i + 1); 25 26 if (second >= 0xDC00 && second <= 0xDFFF) { 27 return ((first - 0xD800) * 0x400) + second - 0xDC00 + 0x10000; 28 } 29 } 30 31 return first; 32}; 33