Solving Uncaught ReferenceError: CodeMirror is not defined Error in JavaScript

Encountering `Uncaught ReferenceError: CodeMirror is not defined` while working on your HTML project? Here's a comprehensive guide to resolve the issue with the CodeMirror library.
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Troubleshooting CodeMirror Integration in JavaScript

If you’re trying to create a code editor using the popular JavaScript library CodeMirror but running into the frustrating Uncaught ReferenceError: CodeMirror is not defined error, you’re not alone! This common issue can be attributed to improper script tag usage or loading sequence in your HTML file. In this post, we will break down the problem and walk you through a simple solution to get CodeMirror working seamlessly in your project.

Understanding the Error

When you attempt to use CodeMirror in your JavaScript, the following error may appear:

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

This indicates that the browser cannot find the CodeMirror definition before it is being called in your code. Usually, this is a result of incorrectly included script tags in your HTML document.

Why This Happens

The underlying reasons for this error include:

Incorrect <script> tags for loading CodeMirror

Using type="module" when it should not be

Loading the JavaScript files in the wrong order

Not having the necessary files at specified paths

Steps to Fix the Issue

To solve this issue, follow these steps to correct the inclusion of the CodeMirror library in your HTML:

Step 1: Check Your HTML Code

Here’s how you initially added the CodeMirror scripts:

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

In your current code, you had type="module" which is unnecessary in this context. It can prevent the proper loading of CodeMirror and cause the reference error.

Step 2: Modify Script Tags

Replace your <script> tags with the following format. Notice that I have removed the type="module" attribute:

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

Step 3: Testing Your Code

Once you have updated the HTML code, load your project in the browser again. If everything is set correctly, the Uncaught ReferenceError: CodeMirror is not defined should no longer appear, and your CodeMirror editor should function as intended.

Conclusion

When you encounter Uncaught ReferenceError: CodeMirror is not defined, it is often a simple fix related to how the libraries are included in your HTML. By ensuring you are using the right script tags and checking your file paths, you can avoid this error altogether. Thank you for reading, and happy coding with CodeMirror!