Finding the Symmetric Difference Between Two Arrays

Arrays are fundamental data structures, and a common operation is to identify the unique elements that exist in one array but not the other, and vice-versa. This challenge focuses on finding the "symmetric difference" between two arrays, which are elements that appear in either array, but not in both. This operation is useful in various scenarios, such as comparing datasets, identifying unique features, or implementing set-like operations.

Problem Description

Your task is to write a Javascript function symmetricDifference(arr1, arr2) that accepts two arrays, arr1 and arr2, as input. The function should return a new array containing all elements that are present in arr1 but not in arr2, combined with all elements that are present in arr2 but not in arr1.

Key Requirements:

• The returned array should only contain unique elements. If an element appears multiple times in one of the input arrays and is not present in the other, it should only appear once in the result.
• The order of elements in the output array does not matter.
• The function should handle arrays containing various data types (numbers, strings, booleans, null, undefined).

Expected Behavior: The function should correctly identify and return elements unique to each array, forming the symmetric difference.

Edge Cases to Consider:

• One or both input arrays are empty.
• Input arrays contain duplicate elements.
• Input arrays contain null or undefined values.
• Input arrays contain a mix of data types.

Examples

Example 1:

Input: arr1 = [1, 2, 3, 4], arr2 = [3, 4, 5, 6]
Output: [1, 2, 5, 6]
Explanation: Elements unique to arr1 are 1 and 2. Elements unique to arr2 are 5 and 6. The symmetric difference is the combination of these: [1, 2, 5, 6].

Example 2:

Input: arr1 = ["apple", "banana", "cherry"], arr2 = ["banana", "date", "fig"]
Output: ["apple", "cherry", "date", "fig"]
Explanation: "apple" and "cherry" are unique to arr1. "date" and "fig" are unique to arr2.

Example 3:

Input: arr1 = [1, 2, 2, 3], arr2 = [3, 4, 4, 5]
Output: [1, 2, 4, 5]
Explanation: Even though '2' appears twice in arr1 and '4' appears twice in arr2, they are unique to their respective arrays when compared to the other. The output contains each unique element only once.

Example 4:

Input: arr1 = [], arr2 = [1, 2, 3]
Output: [1, 2, 3]
Explanation: arr1 is empty, so all elements from arr2 are unique.

Constraints

• The input arrays arr1 and arr2 can have a length of up to 1000 elements.
• Input arrays will be valid Javascript arrays.
• The solution should aim for reasonable performance, ideally better than O(n*m) complexity where n and m are the lengths of the arrays.

Notes

Consider using Javascript's built-in data structures and methods to efficiently track elements and their presence in the arrays. Sets are particularly well-suited for this type of problem due to their ability to store unique values and provide fast lookups.