How to Replace Key Values in an Array of Objects in JavaScript

Learn how to effectively replace key values inside an array of objects in JavaScript using the `map()` method. Follow this step-by-step guide to simplify your coding process.
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Understanding Key Value Replacement in Arrays of Objects

In JavaScript, arrays of objects are a common data structure used to store related information. However, there are times when you may want to replace the values of specific keys in these objects with new values from another object. In this guide, we’ll explore how to accomplish this task seamlessly using the map() method.

The Problem

Let’s say we have an array called purchaseDetails with multiple objects representing different purchases:

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

We also have another object named toReplace that contains new values for certain keys:

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

Goal

The goal here is to replace the amount, purchaseOrder, and purchaseDate keys in the objects within purchaseDetails with the corresponding values from toReplace. The modified array should ultimately look like this:

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

The Solution

Step-by-Step Implementation

Declare the Array with let:
First, ensure that purchaseDetails is declared using let, allowing us to reassign its value later.

Use map() to Create a New Array:
We’ll map over purchaseDetails and merge each object with the toReplace object using the spread operator ....

Here’s the complete code demonstrating this:

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

Explanation of the Code

let purchaseDetails: This allows us to change the variable later, which is necessary since we’ll be creating a new array.

{ ...obj, ...toReplace }: Using the spread operator, we create a new object that includes all properties from obj plus the properties from toReplace. The properties from toReplace will overwrite those from obj if they share the same key.

Final Output

After running the code, you will see that purchaseDetails now contains the updated values:

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

Conclusion

In this post, we effectively tackled the problem of replacing key values in an array of objects in JavaScript using a concise approach with the map() method. This method is not only simple to implement but also ensures that the original array remains unaltered, as it returns a new array with the desired modifications.

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