Find the Duplicate Elements in the Array Hey Coders, Today in this article I'll going to tell you How to find the Duplicate Elements of the array using various methods of JavaScript.  All of these methods will find and return an array containing the duplicate elements from the input array. You can choose the method that suits your requirements and coding style best. Method 1: Using Nested Loops function findDuplicates(arr) {   const duplicates = [];   for (let i = 0; i < arr.length; i++) {     for (let j = i + 1; j < arr.length; j++) {       if (arr[i] === arr[j] && !duplicates.includes(arr[i])) {         duplicates.push(arr[i]);         break;       }     }   }   return duplicates; } const arr = [1, 2, 3, 4, 2, 5, 6, 1]; const duplicates = findDuplicates(arr); console.log(duplicates); // Output: [1, 2] Method 2: Using a Hash Map function findDuplicates(arr) {...