How to Merge Two Array of Objects and Return Specific Keys in JavaScript

Learn how to efficiently merge two arrays of objects in JavaScript while retrieving only the specific keys you want, such as `orderId`, `name`, and `itemName`.
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Merging Two Arrays of Objects in JavaScript

In programming, we often deal with multiple datasets that we need to combine to get meaningful insights. One common scenario is merging two arrays of objects in JavaScript based on a unique identifier. The challenge can arise when you only want to retrieve specific keys from these merged objects rather than all the keys. In this guide, we will explore how to accomplish this with ease.

The Problem

Suppose you have two arrays:

arrOrder, which contains orders with various properties.

arrItem, which contains items with additional details.

Your goal is to merge these arrays based on the itemId property, but you only want to include specific keys in the merged results: orderId, name, and itemName.

Initial Code Attempt

You might start with a working example that merges both arrays but ends up including all properties, which is not what you want. The initial code snippet might look like this:

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

This results in an array containing all the keys from both arrays.

The Solution

To tailor your merged array and only include the desired keys, you need to specify those keys individually in your return statement when mapping over arrOrder. Here’s how you can do it:

Step-by-Step Guide

Finding the Matching Object: Use the find method to get the matching item object based on itemId.

Return Only Desired Keys: Instead of spreading both objects and including all keys, manually create a new object that holds only the keys you want.

Updated Code Example

Here’s the revised version of the code to achieve the desired output:

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

Result

By running the updated code, you will get the following output:

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

Conclusion

When merging arrays of objects in JavaScript, it's essential to control which keys are included in the resulting array. By specifically returning only the keys you need and avoiding the spread operator that brings in all properties, you can efficiently manage the output of your merged data.

Feel free to apply this technique in your projects and tailor the resulting structure to fit your needs!