Merging Arrays of Objects to Get Unique Values in JavaScript

Learn how to effectively `merge arrays of objects` in JavaScript while ensuring unique values and prioritizing data from one array over another.
---

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Merge array of objects and get unique values

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Merging Arrays of Objects in JavaScript: How to Get Unique Values

In JavaScript, working with arrays of objects is a common task. Sometimes, you may find yourself in a situation where you need to merge two arrays containing nested objects, while ensuring that the merged result maintains only unique values. In this guide, we’ll tackle this problem and provide you with a clear, step-by-step solution.

The Problem at Hand

Consider you have two arrays, variants and newVariants, each consisting of objects that share common data fields like color, sizes, and material. The challenge is to merge these arrays in such a way that you get a unique array of objects, with the values from the variants array taking precedence over those in the newVariants array.

Here’s an example of the arrays we are working with:

ARRAY 1

[[See Video to Reveal this Text or Code Snippet]]

ARRAY 2

[[See Video to Reveal this Text or Code Snippet]]

Expected Output

The desired merged output should look like this:

[[See Video to Reveal this Text or Code Snippet]]

Note: ARRAY 1's values will always take precedence over ARRAY 2's.

The Solution Breakdown

To achieve the merging of these arrays while ensuring uniqueness, we can follow a straightforward approach using a combination of the reduce() method and a Map object.

Step 1: Combine the Arrays

First, we’ll concatenate both arrays with newVariants placed before variants. This way, when we reduce the combined array into a Map, the properties from the objects in variants will replace those in newVariants whenever there's overlap.

Step 2: Create a Unique Key and Reduce

Using reduce(), we will build a Map where each entry is keyed by a concatenated string of the values we want to merge by (excluding price). Then we'll ensure that the values are unique by updating the Map accordingly.

Here’s the code to implement this solution:

[[See Video to Reveal this Text or Code Snippet]]

This will yield the merged structure you need with unique values, prioritizing variants data whenever there are overlaps.

Alternative Approach: Order Sensitivity

If you need the order of the output array to be in the priority of variants, here’s an alternative method. You still set up your two arrays, but reverse their order in the merge and use a check to ensure uniqueness.

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

Merging arrays of objects to get unique values can be a bit tricky, especially when you want to maintain the precedence of one array’s data over another’s. By using the strategies outlined above, you’ll be well-equipped to tackle similar challenges in your JavaScript projects.

Now you are ready to streamline your data handling in JavaScript like a pro! Happy coding!