node js remove duplicates from array code example

Example 1: js delete duplicates from array

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

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

Example 2: how to remove duplicates in array in javascript

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

Example 3: javascript remove duplicates from array

var myArr = [1, 2, 2, 2, 3];
var mySet = new Set(myArr);
myArr = [...mySet];
console.log(myArr);
// 1, 2, 3

Example 4: javascript remove duplicate strings from array

//ES6
let uniqueArray = [...new Set(arrayWithDuplicates)];

//Alternative
function removeArrayDuplicates(arrayWithDuplicates) {
    let seen = {};
    let uniqueArray = [];
    let len = arrayWithDuplicates.length;
    let j = 0;
    for(let i = 0; i < len; i++) {
         let item = arrayWithDuplicates[i];
         if(seen[item] !== 1) {
               seen[item] = 1;
               uniqueArray[j++] = item;
         }
    }
    return uniqueArray;
}

Example 5: javascript remove uniques from array

function getNotUnique(array) {
    var map = new Map();
    array.forEach(a => map.set(a, (map.get(a) || 0) + 1));
    return array.filter(a => map.get(a) > 1);
}

console.log(getNotUnique([1, 2, 2, 4, 4])); //[2, 2, 4, 4]
console.log(getNotUnique([1, 2, 3] )); //[]

Example 6: remove duplicate array es6

let a = [10,20,30,10,30];
let b = [... new Set(a)];
console.log(b);