1const names = ['John', 'Paul', 'George', 'Ringo', 'John'];
2
3let unique = [...new Set(names)];
4console.log(unique); // 'John', 'Paul', 'George', 'Ringo'
1let arr = [1,2,3,1,1,1,4,5]
2
3let filtered = arr.filter((item,index) => arr.indexOf(item) === index)
4
5 console.log(filtered) // [1,2,3,4,5]
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"
1const numbers = [1 , 21, 21, 34 ,12 ,34 ,12];
2const removeRepeatNumbers = array => [... new Set(array)]
3removeRepeatNumbers(numbers) // [ 1, 21, 34, 12 ]
1function toUniqueArray(a){
2 var newArr = [];
3 for (var i = 0; i < a.length; i++) {
4 if (newArr.indexOf(a[i]) === -1) {
5 newArr.push(a[i]);
6 }
7 }
8 return newArr;
9}
10var colors = ["red","red","green","green","green"];
11var colorsUnique=toUniqueArray(colors); // ["red","green"]
1function onlyUnique(value, index, self) {
2 return self.indexOf(value) === index;
3}
4
5// usage example:
6var a = ['a', 1, 'a', 2, '1'];
7var unique = a.filter(onlyUnique);
8
9console.log(unique); // ['a', 1, 2, '1']