source: trip-planner-front/node_modules/array-uniq/index.js@ 59329aa

Last change on this file since 59329aa was 6a3a178, checked in by Ema <ema_spirova@…>, 3 years ago

initial commit

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Line 
1'use strict';
2
3// there's 3 implementations written in increasing order of efficiency
4
5// 1 - no Set type is defined
6function uniqNoSet(arr) {
7 var ret = [];
8
9 for (var i = 0; i < arr.length; i++) {
10 if (ret.indexOf(arr[i]) === -1) {
11 ret.push(arr[i]);
12 }
13 }
14
15 return ret;
16}
17
18// 2 - a simple Set type is defined
19function uniqSet(arr) {
20 var seen = new Set();
21 return arr.filter(function (el) {
22 if (!seen.has(el)) {
23 seen.add(el);
24 return true;
25 }
26
27 return false;
28 });
29}
30
31// 3 - a standard Set type is defined and it has a forEach method
32function uniqSetWithForEach(arr) {
33 var ret = [];
34
35 (new Set(arr)).forEach(function (el) {
36 ret.push(el);
37 });
38
39 return ret;
40}
41
42// V8 currently has a broken implementation
43// https://github.com/joyent/node/issues/8449
44function doesForEachActuallyWork() {
45 var ret = false;
46
47 (new Set([true])).forEach(function (el) {
48 ret = el;
49 });
50
51 return ret === true;
52}
53
54if ('Set' in global) {
55 if (typeof Set.prototype.forEach === 'function' && doesForEachActuallyWork()) {
56 module.exports = uniqSetWithForEach;
57 } else {
58 module.exports = uniqSet;
59 }
60} else {
61 module.exports = uniqNoSet;
62}
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