How to Merge Two Arrays of Objects in JavaScript Without Duplicates

Learn how to effectively merge two arrays of objects in JavaScript without creating duplicates. This guide provides a clear solution using modern JavaScript features.
---

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: Unable to add second array object value into first array of objects in javascript

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
How to Merge Two Arrays of Objects in JavaScript Without Duplicates

If you’re working with arrays in JavaScript, you might occasionally find yourself needing to combine multiple arrays of objects into a single array, while also ensuring that no duplicate values are created. This post addresses a common problem faced by many developers: merging two arrays of objects without duplicating the existing data. Let’s dive into the solution step by step.

The Problem

Let’s say you have two arrays: firstArray and secondArray. For example:

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

The goal is to merge them into a single array with the following structure:

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

The Solution

Instead of relying on nested for loops—which can lead to issues like duplicates—JavaScript provides modern array methods that simplify this process. Specifically, we can use the .map() method to build our new array efficiently.

Step-by-Step Breakdown

Mapping the Outer Objects: We’ll start by mapping through firstArray to create new objects, while also setting up the new data values.

Mapping the Inner Data: For each object in firstArray, we'll map through the data property and combine it with the corresponding element from secondArray.

Implementation

Here’s how you can implement this solution in your code:

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

Explanation

Spread Syntax: The use of ...obj and ...inner allows us to copy the properties of the existing objects and merge them with new properties from secondArray.

Indexing: The index i in the inner map method helps us align each data with its corresponding value from secondArray, creating the desired structure without duplicates.

Conclusion

By utilizing the .map() method along with the spread syntax, you can efficiently merge two arrays of objects in JavaScript without worrying about duplicates. This approach is not only cleaner and more readable but it also leverages modern JavaScript features to improve your code's performance and maintainability.

If you find yourself needing to work with arrays in JavaScript, remember this technique for merging arrays efficiently. Happy coding!