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