how to check duplicates in array javascript code example
Example 1: count duplicates array js
uniqueCount = ["a","b","c","d","d","e","a","b","c","f","g","h","h","h","e","a"];
var count = {};
uniqueCount.forEach(function(i) { count[i] = (count[i]||0) + 1;});
console.log(count);
Example 2: 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))
console.log([...new Set(findDuplicates(strArray))])
Example 3: javascript duplicate an array
let arr =["a","b","c"];
const duplicate = [...arr];
const duplicate = Array.from(arr);