javascript merge arrays remove duplicates 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: merge array no duiplicates js

let array1 = ['a','b','c'];
let array2 = ['c','c','d','e'];
let array3 = array1.concat(array2);
array3 = [...new Set([...array1,...array2])]; // O(n)

Example 3: 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'