removing duplicates from array javascript

1const names = ['John', 'Paul', 'George', 'Ringo', 'John'];
2
3let unique = [...new Set(names)];
4console.log(unique); // 'John', 'Paul', 'George', 'Ringo'

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"

1// for TypeScript and JavaScript
2const initialArray = ['a', 'a', 'b',]
3finalArray = Array.from(new Set(initialArray)); // a, b

1const numbers = [1 , 21, 21, 34 ,12 ,34 ,12];
2const removeRepeatNumbers = array => [... new Set(array)]
3removeRepeatNumbers(numbers) // [ 1, 21, 34, 12 ]

1var names = ["Mike","Matt","Nancy","Adam","Jenny","Nancy","Carl"];
2var uniqueNames = [];
3$.each(names, function(i, el){
4    if($.inArray(el, uniqueNames) === -1) uniqueNames.push(el);
5});
6

1var car = ["Saab","Volvo","BMW","Saab","BMW",];
2var cars = [...new Set(car)]
3document.getElementById("demo").innerHTML = cars;