1// 1. filter()
2function removeDuplicates(array) {
3 return array.filter((a, b) => array.indexOf(a) === b)
4};
5// 2. forEach()
6function removeDuplicates(array) {
7 let x = {};
8 array.forEach(function(i) {
9 if(!x[i]) {
10 x[i] = true
11 }
12 })
13 return Object.keys(x)
14};
15// 3. Set
16function removeDuplicates(array) {
17 array.splice(0, array.length, ...(new Set(array)))
18};
19// 4. map()
20function removeDuplicates(array) {
21 let a = []
22 array.map(x =>
23 if(!a.includes(x) {
24 a.push(x)
25 })
26 return a
27};
28/THIS SITE/ "https://dev.to/mshin1995/back-to-basics-removing-duplicates-from-an-array-55he#comments"