Solving the undefined Issue When Receiving Data from a Function in React

Learn how to properly receive data returned by a function in a React project. This guide addresses the common `undefined` issue encountered when fetching data from Firebase.
---

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Unable to receive data returned by a function

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Solving the undefined Issue When Receiving Data from a Function in React

In the world of React development, it's not uncommon to encounter scenarios where you need to fetch data from external sources, such as databases or APIs. One frustrating problem developers often face is receiving undefined when trying to handle such data. In this guide, we will explore a specific case in a React project that involves fetching user contact details but hits a wall when it comes to accessing the returned data properly.

The Problem: Cannot Receive Data Returned by a Function

Here is a brief overview of the relevant code segments:

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

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

The Solution: Properly Returning Data from Asynchronous Functions

To resolve this problem, we need to ensure that getUserContacts() can return meaningful data to the calling function synchronously. We can achieve this by restructuring the function to return the promise generated by Firestore rather than just the array itself.

Step-by-Step Implementation

Modify the getUserContacts() function: Update your function to return the promise chain so that the calling component can handle the asynchronous data loading.

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

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

Summary

To sum it up, the undefined issue when trying to retrieve data from your function stemmed from improper asynchronous handling. By restructuring your code to ensure all promises are awaited and that the final result is properly returned to the calling component, you can effectively receive and utilize the data in your React application.

Final Thoughts

This is a common pitfall in React development, especially when working with asynchronous operations. Take care to make sure your functions return promises when dealing with async data, and always handle them properly in the component that calls them. Happy coding!