How to Fix undefined State Issue When Getting Data from an API in React

Discover how to effectively fetch data from an API and correctly store it in state in React without encountering `undefined` values.
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Fixing the undefined State Issue When Fetching Data from an API in React

As a beginner in React, you might encounter some frustrating issues when trying to fetch data from an API and store it in your component's state. One common problem is when the state still shows undefined after you make a network request. In this guide, we will explore the issue and provide a step-by-step solution to ensure your state updates correctly with the fetched data.

The Problem

You have set up a function to fetch data from an API using axios and attempt to store the returned data in a state variable. However, when you check the state, it shows undefined. Here's an overview of the relevant code that leads to this issue:

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

In your component, you are trying to use this function as follows:

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

The expected behavior is that setSearchedData(data) updates the state with the fetched data. However, it doesn't seem to work as intended.

Understanding the Issue

The Solution

Let’s fix the searchSong function to ensure it returns the fetched data properly:

Return the Promise: The searchSong function needs to return the result of the axios request so that it can be awaited in your component function.

Here's how the modified function should look:

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

Alternatively, you can simplify the function using an implicit return with an arrow function:

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

Another option, utilizing asynchronous syntax, would be:

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

Updating the Component

Now that searchSong properly returns the data, you can continue using it in your songInput function as follows:

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

Conclusion

By returning the result from the searchSong function, you ensure that the awaited value in your component is defined and holds the expected data from the API. This solution allows you to correctly set the state and avoid the undefined issue that many beginners face when integrating API calls in React.

If you still encounter issues or have further questions, don't hesitate to seek help or explore more about React's state management and asynchronous functions. Happy coding!