How to Find the Symmetric Difference Between Two Arrays in JavaScript

Source: Dev.to

Approach Overview

We compare two arrays and return a new array that contains only the values that exist in one array but not in both. In other words, we remove the values that appear in both arrays.

Step 1: Filter arrayOne

arrayOne.filter(item => !arrayTwo.includes(item))

For each item in arrayOne, we check if it is not included in arrayTwo. Only the values that do not exist in arrayTwo are returned.

Step 2: Filter arrayTwo

arrayTwo.filter(item => !arrayOne.includes(item))

This time we return only the values that are not included in arrayOne.

Step 3: Merge the results

const result = arrayOne
  .filter(item => !arrayTwo.includes(item))
  .concat(arrayTwo.filter(item => !arrayOne.includes(item)));

We merge the two filtered arrays using Array.prototype.concat(). The final array (result) contains the symmetric difference between the two original arrays—the values that appear in only one of the arrays.

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This method is simple, readable, and easy to understand, making it a good choice for beginners. Feel free to share your own solution in the comments! 🔥