How to Retrieve and Display Data in ReactJS using reader.onload and Axios

Introduction:

Struggling to display data in your ReactJS application using reader.onload and Axios? Don’t worry, you’re not alone! Many developers face challenges when it comes to retrieving and rendering data from APIs. In this comprehensive guide, we’ll explore a scenario where an array of data needs to be fetched and displayed using these methods. By the end of this article, you’ll have a clear understanding of how to overcome this issue. Let’s dive in and get your ReactJS application up and running smoothly!

Understanding the Problem

Subheading: The Data Display Issue Have you encountered a situation where the data fetched from an API using Axios and reader.onload fails to display correctly in your ReactJS application? Let’s examine the problem more closely to find a solution.

Analyzing the Code

Subheading: The Fetch and Render Logic In the provided code snippet, there’s an array of data that needs to be fetched and rendered using reader.onload and Axios. Let’s break down the code and understand the steps involved.

Fetching the Data Subheading:

Fetching Attachments Within the Render component, there’s a fetchAttachment function that is responsible for fetching the data from the API. It uses the Axios library to make the request, specifying the response type as “blob”. This function is called for each item in the array.

Handling the Response Subheading:

FileReader and reader.onload After successfully fetching the data, the code creates a FileReader object and uses it to read the data. The reader.onload event is triggered when the reading operation is complete. Inside this event handler, a link variable is assigned the result of the reader, which represents the data in a URL format.

Displaying the Data Subheading:

Passing the Link to the Item Component To display the fetched data, the link variable needs to be passed as a prop to the Item component. However, there is a problem with the current implementation, which we’ll address in the next section.

Resolving the Issue Subheading:

Handling Asynchronous Rendering The main issue lies in the asynchronous nature of the fetchAttachment function. Since it returns a promise, it cannot be directly used within the map function. To resolve this, we’ll make use of React’s useState hook to store the fetched data and ensure synchronous rendering.

Implementing the Solution Subheading:

Modifying the Code Here’s an example of how the code can be modified to resolve the issue:

1. Import the useState hook from React.
2. Initialize a state variable to store the links: const [links, setLinks] = useState([] );
3. Inside the fetchAttachment function, instead of directly returning the link, update the state using setLinks([...links, link] ).
4. In the Render component, iterate over the links array instead of the arr array. Pass the individual link to the Item component.

Conclusion

Retrieving and displaying data in ReactJS using reader.onload and Axios can be achieved by addressing the asynchronous rendering issue and properly managing the state. By following the steps outlined in this guide, you’ll be able to fetch and render data seamlessly in your ReactJS application. Remember to stay curious, explore different approaches, and continue honing your coding skills.

By following these steps, you can create a blog post for WordPress that effectively explains the issue, provides a solution, and guides your readers through the implementation process in a conversational and professional tone.