javascript how to duplicate an element code example
Example 1: how to check for duplicate syntax in javascript
let strArray = [ "q", "w", "w", "w", "e", "i", "u", "r"];
let findDuplicates = arr => arr.filter((item, index) => arr.indexOf(item) != index)
console.log(findDuplicates(strArray)) // All duplicates
console.log([...new Set(findDuplicates(strArray))]) // Unique duplicates
Example 2: javascript duplicate an array
let arr =["a","b","c"];
// ES6 way
const duplicate = [...arr];
// older method
const duplicate = Array.from(arr);