Why is my function returning an empty array in SwiftUI?

Discover why your SwiftUI function returns an `empty array` and learn how to fix it for successful data fetching in your app.
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This video is based on the question https://stackoverflow.com/q/71587360/ asked by the user 'XNQ' ( https://stackoverflow.com/u/16547651/ ) and on the answer https://stackoverflow.com/a/71587797/ provided by the user 'workingdog support Ukraine' ( https://stackoverflow.com/u/11969817/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Why is my Function Returning an Empty Array in SwiftUI?

If you're a developer working with SwiftUI, you may encounter situations where your functions don't return the expected results. One common issue is when your function returns an empty array. This guide will explore a specific scenario and explain how to resolve it.

The Problem

You have implemented a function that fetches messages from a remote API, but when you attempt to display the results in your SwiftUI view, the output is an empty array. The setup includes ObservableObject and a SwiftUI View, but despite fetching the messages correctly, they don't appear when you try to print them later in your view.

Code Overview

Here's a simplified version of your code:

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

And your SwiftUI view looks like this:

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

However, both print statements return (), or [], indicating that the messages array is empty.

The Solution

The primary reason you're seeing an empty array in your HomeTab view is that the fetching of data is asynchronous. When you call getMsgs.fetchMessages(), the data fetching does not occur instantly. Instead, it takes some time to retrieve and process the messages, leading to a timing issue.

Step-by-Step Fix

Avoid Printing Before Data is Available: Do not try to print getMsgs.messages immediately after calling fetchMessages(), as the data has not been fetched yet.

Simulate Data Fetching Correctly: Update your SwiftUI view to properly handle the fetched data after it becomes available.

Here’s the revised code for your HomeTab view:

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

Key Takeaways

Asynchronous Data Fetching: Understand that network calls and data fetching in SwiftUI are asynchronous. This means you should wait for the data to be available in the state.

@ StateObject: SwiftUI's observable objects, such as your GetMessages class, notify views of state changes, prompting the UI to update.

Avoid Direct Prints: When troubleshooting, avoid printing state variables before they are expected to be filled with data.

By following this guide, you should now be able to resolve the issue of receiving an empty array in your SwiftUI application and successfully display your messages. Happy coding!

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