source: trip-planner-front/node_modules/abab/lib/btoa.js

Last change on this file was 6a3a178, checked in by Ema <ema_spirova@…>, 3 years ago

initial commit

  • Property mode set to 100644
File size: 1.5 KB
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[6a3a178]1"use strict";
2
3/**
4 * btoa() as defined by the HTML and Infra specs, which mostly just references
5 * RFC 4648.
6 */
7function btoa(s) {
8 let i;
9 // String conversion as required by Web IDL.
10 s = `${s}`;
11 // "The btoa() method must throw an "InvalidCharacterError" DOMException if
12 // data contains any character whose code point is greater than U+00FF."
13 for (i = 0; i < s.length; i++) {
14 if (s.charCodeAt(i) > 255) {
15 return null;
16 }
17 }
18 let out = "";
19 for (i = 0; i < s.length; i += 3) {
20 const groupsOfSix = [undefined, undefined, undefined, undefined];
21 groupsOfSix[0] = s.charCodeAt(i) >> 2;
22 groupsOfSix[1] = (s.charCodeAt(i) & 0x03) << 4;
23 if (s.length > i + 1) {
24 groupsOfSix[1] |= s.charCodeAt(i + 1) >> 4;
25 groupsOfSix[2] = (s.charCodeAt(i + 1) & 0x0f) << 2;
26 }
27 if (s.length > i + 2) {
28 groupsOfSix[2] |= s.charCodeAt(i + 2) >> 6;
29 groupsOfSix[3] = s.charCodeAt(i + 2) & 0x3f;
30 }
31 for (let j = 0; j < groupsOfSix.length; j++) {
32 if (typeof groupsOfSix[j] === "undefined") {
33 out += "=";
34 } else {
35 out += btoaLookup(groupsOfSix[j]);
36 }
37 }
38 }
39 return out;
40}
41
42/**
43 * Lookup table for btoa(), which converts a six-bit number into the
44 * corresponding ASCII character.
45 */
46const keystr =
47 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
48
49function btoaLookup(index) {
50 if (index >= 0 && index < 64) {
51 return keystr[index];
52 }
53
54 // Throw INVALID_CHARACTER_ERR exception here -- won't be hit in the tests.
55 return undefined;
56}
57
58module.exports = btoa;
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