how to remove duplicates in array in javascript

const names = ['John', 'Paul', 'George', 'Ringo', 'John'];

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

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3.6

Shariq shamsi 100 points

                                    const numbers = [1 , 21, 21, 34 ,12 ,34 ,12];
const removeRepeatNumbers = array =&gt; [... new Set(array)]
removeRepeatNumbers(numbers) // [ 1, 21, 34, 12 ]

Thank you! 5

3.6 (5 Votes)

4.43

Captain Cranium 115 points

                                    const names = ['John', 'Paul', 'George', 'Ringo', 'John'];

let x = (names) =&gt; names.filter((v,i) =&gt; names.indexOf(v) === i)
x(names); // 'John', 'Paul', 'George', 'Ringo'

Thank you! 7

4.43 (7 Votes)

Aj Morales 120 points

                                    let arr = [1,2,3,1,1,1,4,5]
    
let filtered = arr.filter((item,index) =&gt; arr.indexOf(item) === index)
    
 console.log(filtered) // [1,2,3,4,5]

Thank you! 5

4 (5 Votes)

3.33

Nesreen t Alkam 105 points

                                    function toUniqueArray(a){<br/>    var newArr = [];<br/>    for (var i = 0; i &lt; a.length; i++) {<br/>        if (newArr.indexOf(a[i]) === -1) {<br/>            newArr.push(a[i]);<br/>        }<br/>    }<br/>  return newArr;<br/>}<br/>var colors = [&quot;red&quot;,&quot;red&quot;,&quot;green&quot;,&quot;green&quot;,&quot;green&quot;];<br/>var colorsUnique=toUniqueArray(colors); // [&quot;red&quot;,&quot;green&quot;]

Thank you! 3

3.33 (3 Votes)

Edward Russell 110 points

                                    // 1. filter()
function removeDuplicates(array) {
  return array.filter((a, b) =&gt; array.indexOf(a) === b)
};
// 2. forEach()
function removeDuplicates(array) {
  let x = {};
  array.forEach(function(i) {
    if(!x[i]) {
      x[i] = true
    }
  })
  return Object.keys(x)
};
// 3. Set
function removeDuplicates(array) {
  array.splice(0, array.length, ...(new Set(array)))
};
// 4. map()
function removeDuplicates(array) {
  let a = []
  array.map(x =&gt; 
    if(!a.includes(x) {
      a.push(x)
    })
  return a
};
/THIS SITE/ &quot;https://dev.to/mshin1995/back-to-basics-removing-duplicates-from-an-array-55he#comments&quot;

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