--- /dev/null
+/* 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;
+};