Find the Intersection of Two Arrays

Given two integer arrays, array1 and array2, write a function in JavaScript that finds the intersection of these two arrays. The intersection of two arrays is a list of unique elements that are present in both arrays. Your function should return the intersection in any order.

Constraints:

• The arrays may contain duplicate elements, but the output must contain only unique elements.
• The function should not use any built-in library methods for set operations.
• Assume the arrays are not necessarily sorted.
• The length of both arrays (array1 and array2) will not exceed 10^4.

Inputs:

• array1: An array of integers. Example: [1, 2, 2, 1]
• array2: An array of integers. Example: [2, 2]

Outputs:

• Return an array containing the unique elements that are present in both array1 and array2. Example: [2]

Examples:

Example 1:

• Input: array1 = [4,9,5], array2 = [9,4,9,8,4]
• Output: [9,4] or [4,9]

Example 2:

• Input: array1 = [1,2,2,1], array2 = [2,2]
• Output: [2]

Example 3:

• Input: array1 = [1,2], array2 = [1,1]
• Output: [1]