Скачать или смотреть Adding a userRating Property to an Array of Objects with Axios

Learn how to effectively add a `userRating` property to an array of objects in JavaScript using Axios, including common pitfalls and best practices.
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How to Add a userRating Property to an Array of Objects with Axios

When working with arrays of objects in JavaScript, you might find the need to modify or enrich the data you're dealing with. One common scenario is adding a new property to each object in an array. If you're using Axios to retrieve data from an API, this can be especially useful. In this guide, we will explore how to add a userRating property to each object in an array when making API requests using Axios.

The Problem: Adding a userRating Property

You might encounter a situation where you want to fetch a list of movies from an API and then add a new property, userRating, set to null for each movie. Let’s look at a common attempt and why it may not work as intended.

Sample Code Attempt

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

In this example, although you are trying to use the map method to modify each movie object, the original array remains unchanged due to how map operates.

Understanding the map Method

The map method in JavaScript:

Returns a new array: It does not change the original array.

Transforms elements: It creates a new array populated with the results of calling a provided function on every element in the calling array.

In your code, you're creating a new transformed array with map, but you didn’t assign that transformed array to anything, which is why it doesn’t work.

Solution: Properly Using map to Modify Objects

To effectively add the userRating property, you need to make sure you are using the map method properly to create a new array and then set it to your movie list. Here’s how to do it correctly:

The Correct Approach

Here’s the modified version of your function:

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

Code Breakdown

response.data.map(...): This takes the incoming data from your API response and applies the map function to it.

...movie: This spreads each existing movie object’s properties.

userRating: null: This adds a new property userRating with a value of null to each movie object.

setMovieList(updatedResponse): Finally, you update your state with the newly modified array.

Conclusion

By applying the correct use of the map method, you can easily add new properties to objects within an array returned from Axios calls. This pattern is a powerful way to enrich your data before using it in your application.

Now you can confidently add properties like userRating to your API response objects. If you have any further questions or run into issues, feel free to reach out in the comments!