Find duplicates in an array using javascript

Problem :

Given an array of positive integers find all the duplicate elements.

Algorithm :

• Iterate over the array using forEach
  • Find if there is a duplicate for the element using indexOf
  • indexOf takes two arguments first the element and the second one is the starting index
  • We provide the starting index as the index + 1 where index is the index of the current element
  • We will find if the same element exists on the right hand side of that element or not

  • If there’s a duplicate and the element is not already being added to the result then push it to the array.

Solution :

Further reading :

• Array.prototype.indexOf()

• Array.prototype.forEach()