(using javascript) Have the function ArrayChallenge(arr) take the array of numbers stored in arr and determine the total number of duplicate entries. The objective is to remove duplicate elements from an array.

For example if the input is [1, 2, 2, 2, 3] then your program should output 2 because there are two duplicates of one of the elements.

Put/ implement the solution into this starter code below:

function ArrayChallenge(arr) {

// code goes here

return arr;

// keep this function call here

console.log(ArrayChallenge(readline()));

Examples of inputs and expected outputs:

Input: [0,-2,-2,5,5,5] Output: 3

Input: [100,2,101,4] Output: 0