-
-
Notifications
You must be signed in to change notification settings - Fork 1.6k
/
esnext.uint8-array.to-base64.js
47 lines (40 loc) · 1.58 KB
/
esnext.uint8-array.to-base64.js
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
'use strict';
var $ = require('../internals/export');
var global = require('../internals/global');
var uncurryThis = require('../internals/function-uncurry-this');
var anObjectOrUndefined = require('../internals/an-object-or-undefined');
var anUint8Array = require('../internals/an-uint8-array');
var base64Map = require('../internals/base64-map');
var getAlphabetOption = require('../internals/get-alphabet-option');
var base64Alphabet = base64Map.i2c;
var base64UrlAlphabet = base64Map.i2cUrl;
var Uint8Array = global.Uint8Array;
var charAt = uncurryThis(''.charAt);
// `Uint8Array.prototype.toBase64` method
// https://github.com/tc39/proposal-arraybuffer-base64
if (Uint8Array) $({ target: 'Uint8Array', proto: true, forced: true }, {
toBase64: function toBase64(/* options */) {
var array = anUint8Array(this);
var options = arguments.length ? anObjectOrUndefined(arguments[0]) : undefined;
var alphabet = getAlphabetOption(options) === 'base64' ? base64Alphabet : base64UrlAlphabet;
var result = '';
var i = 0;
var length = array.length;
var triplet;
var at = function (shift) {
return charAt(alphabet, (triplet >> (6 * shift)) & 63);
};
for (; i + 2 < length; i += 3) {
triplet = (array[i] << 16) + (array[i + 1] << 8) + array[i + 2];
result += at(3) + at(2) + at(1) + at(0);
}
if (i + 2 === length) {
triplet = (array[i] << 16) + (array[i + 1] << 8);
result += at(3) + at(2) + at(1) + '=';
} else if (i + 1 === length) {
triplet = array[i] << 16;
result += at(3) + at(2) + '==';
}
return result;
}
});