Скачать или смотреть Fixing Uncaught ReferenceError: deleted1 is not defined in Your JavaScript Code

Learn how to resolve the common JavaScript error: `Uncaught ReferenceError: deleted1 is not defined` in the context of Firebase and HTML. Discover best practices for defining functions and handling events effectively.
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This video is based on the question https://stackoverflow.com/q/69794305/ asked by the user 'programming newbee' ( https://stackoverflow.com/u/17296068/ ) and on the answer https://stackoverflow.com/a/69865313/ provided by the user 'Professor Abronsius' ( https://stackoverflow.com/u/3603681/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Resolving the Uncaught ReferenceError: deleted1 is not defined

If you’ve encountered the error message “Uncaught ReferenceError: deleted1 is not defined”, you're not alone. Many developers have faced this issue while working with JavaScript, especially in the context of database operations using Firebase. This guide will help you understand the cause of the error and present a well-structured solution.

Understanding the Problem

The error typically indicates that the JavaScript function deleted1 is being called before it has been properly defined. This can often happen when using inline event handlers directly in the HTML markup. In your case, the function is defined within the scope of a forEach loop, which can lead to issues when trying to call it from an HTML element.

The Context

In your existing JavaScript code, the deleted1 function is intended to delete entries from a Firestore database. The function is attached to a button that is generated dynamically as part of a table row. However, due to the scoping of JavaScript, the function isn't accessible globally when the button is clicked.

Solution Breakdown

Here is an organized approach to address the issue:

Step 1: Redefine the deleted1 Function

Instead of defining the deleted1 function inside the forEach loop, we should define it outside. This ensures that the function is available globally and can be called from anywhere in your code.

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

Step 2: Utilizing Event Listeners

Instead of using inline JavaScript in your HTML, it's a better practice to separate the concerns by adding event listeners in your JavaScript code after all HTML elements have been created. This reduces errors and makes your code cleaner.

Step 3: Updating the Button Creation Logic

In the part of your code that generates the delete button, you should use a data attribute to store the id and then attach an event listener that will call the deleted1 function when the button is clicked.

Here’s how the updated logic might look:

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

Conclusion

By restructuring your code to define functions in a broader scope and using event listeners for elements created dynamically, you can avoid the Uncaught ReferenceError and create a cleaner, more maintainable JavaScript application.

If you follow the practices outlined in this blog, you'll mitigate similar issues in the future, resulting in a smoother development experience. Happy coding!