array no duplicates javascript 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: javascript remove duplicate in arrays

// 1. filter()
function removeDuplicates(array) {
  return array.filter((a, b) => 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 => 
    if(!a.includes(x) {
      a.push(x)
    })
  return a
};
/THIS SITE/ "https://dev.to/mshin1995/back-to-basics-removing-duplicates-from-an-array-55he#comments"

Example 3: removing duplicates in array javascript

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

Example 4: javascript remove duplicates from array

unique = [...new Set(arr)];   // where arr contains duplicate elements

Example 5: 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 6: js delete duplicates from array

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

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