How to Return an Object to an Array Using the Fetch API in JavaScript

Discover how to effectively return objects from a fetch API call and populate an array properly in JavaScript. Learn to avoid common pitfalls with asynchronous operations.
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Understanding How to Return an Object to an Array with the Fetch API in JavaScript

The Problem

You're trying to create a new array, accdata, that contains specific objects from an existing array, data. Inside your map() function, you are making asynchronous calls to an API using the fetch API and running into trouble. Specifically, the objects you want to return are only accessible within the .then() method of your fetch operation, making it impossible to properly populate accdata directly.

Example Code Snippet

Here's a simplified version of the code you're working with:

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

What's Going Wrong?

In the code above, what's happening is that your map() function is returning an array of promises instead of the actual objects you're after. Each promise resolves when the fetch call is complete, but the data isn't ready when you want to use it.

A Solution to the Problem

Return the Promise Correctly

To solve this problem, you need to ensure that you are returning the result of the fetch operation itself. Here's how you can adjust your code:

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

This will generate an array filled with promises that resolve to each when the API returns a valid response or undefined if there's an error or a null result.

Utilize Async/Await for a Cleaner Approach

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

Explanation of the Solution

Async Functions: By declaring the function inside map() as async, you can use the await keyword to pause execution until the fetch call resolves. This simplifies handling promises.

Conclusion