Скачать или смотреть Fixing React createRef current is null Issue in Your Navbar Component

Learn how to resolve the `current is null` error when using `createRef` in React, and make your Navbar responsive without any issues.
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This video is based on the question https://stackoverflow.com/q/75631087/ asked by the user 'ClassyCrafter' ( https://stackoverflow.com/u/21328139/ ) and on the answer https://stackoverflow.com/a/75631135/ provided by the user 'Unmitigated' ( https://stackoverflow.com/u/9513184/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Fixing the React createRef current is null Issue in Your Navbar Component

If you're working on a React project, you might have come across the frustrating Uncaught TypeError: Cannot read properties of null (reading 'style') error. This often occurs when you are using createRef but the current property returns null. In this post, we will dive into understanding why this happens and how to fix it, especially in the context of creating a responsive navigation bar (Navbar).

Understanding the Problem

In the provided code, the Navbar component uses createRef to reference HTML elements, specifically the navigation bar and a button that appears when the screen width is less than 768 pixels. The error arises because the current property of ref is null when the component is trying to access it, which subsequently leads to attempts to read properties of null, causing the application to crash.

Key Points Leading to the Error:

Function Call during Render: The key mistake in the render method is that it directly calls the navAppear function within the onClick event. This causes the function to execute immediately when the component renders, instead of waiting for a user click.

Binding Context: There is also an issue related to the this context. Not binding the navAppear function correctly can lead to it executing in the wrong context, potentially causing similar issues.

Solution Overview

Let’s break down how to fix the issue step-by-step, ensuring that your NavBar behaves as expected.

Step 1: Correct the Function Call in onClick

Instead of directly calling this.navAppear() in the onClick, we need to pass the function reference without invoking it. This way, navAppear will get called once the user clicks the button, not when the component renders.

Replace this code line:

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

With this:

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

Step 2: Bind the this Context

By using .bind(this), we ensure that the navAppear function retains the correct reference to the Navbar instance. This is crucial since it allows the method to access the properties and methods of the class.

Revised Button Code

Here's how the button code should look after these corrections:

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

Conclusion

By implementing these changes, you should no longer experience the current is null error in your responsive Navbar component. Here’s a quick recap of the necessary adjustments:

Ensure you pass a function reference to onClick by using .bind(this).

Avoid directly calling methods in the rendering phase to prevent unexpected behavior.

With these simple changes, your Navbar will now work as intended, appearing when appropriate and maintaining the responsiveness you aim for in modern web applications.

Feel free to experiment with the layout and styling to match your brand, and happy coding with React!