How to Properly Return Results and Errors from MySQL Queries in Node.js

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The Challenge: Returning Results and Errors

Imagine you have a function called createProduct that performs an SQL insertion into your MySQL database. The goal is to straightforwardly return either the resulting data or any encountered error. However, if you try returning the result directly from within the query callback, you'll inevitably run into timing issues — the return statement executes before the asynchronous query completes. This can lead to confusion and erratic behavior in your application.

Example of the Problematic Code

Here’s an example of code illustrating the problem:

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

The Key Issue

The Solution: Using Promises and Async/Await

To successfully return results or errors from your MySQL operations, we can refactor the createProduct function to leverage Promises along with async/await. This will ensure that we can handle asynchronous code much more elegantly and without confusion.

Refactored Code Example

Here's how you can write your createProduct function using a Promise:

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

Explanation of the Refactored Code

Error Handling: In the promise, if there's an error, we call rej(err) which will signal that the operation failed, allowing you to catch errors when calling this function.

Using Async/Await: When you invoke createProduct(data), you can simply use await to pause execution until the promise resolves, giving you direct access to the result or error in a clean manner.

Conclusion: Simplifying Database Interactions

If you found this guide helpful, don’t hesitate to share your thoughts or ask further questions in the comments below!