How to Keep Typings and Avoid Overwriting Mongoose Models in Next.js with TypeScript

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Understanding the Problem

In your Mongoose setup, you might define a model like this:

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

However, if your code runs multiple times, Mongoose will throw an OverwriteModelError if it encounters a model with the same name. This error commonly arises in development when the application is hot-reloaded or when server-side rendering is in action.

The Occurrence of OverwriteModelError

Error Message: OverwriteModelError: Cannot overwrite 'UserAccountData' model once compiled.

To solve this, many developers resort to checking whether the model already exists in Mongoose's models collection before creating a new one.

Solution: Avoiding Overwrites While Keeping Typings

Let's explore a clean solution to avoid this error while ensuring you retain TypeScript typings. The fix involves modifying your model creation code:

Check Existing Models: Before defining a new model, check if it's already defined in Mongoose models.

Utilize TypeScript Correctly: Ensure that your model maintains typings correctly.

Here is the code solution to implement:

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

Explanation of the Code

The interface IUserAccountData defines the properties of the MongoDB document, ensuring TypeScript understands the shape of your data.

The Schema is created as usual but ensure naming conventions are consistent (e.g., spelling Address correctly).

The correct typing is applied to the model to ensure TypeScript does not lose track of the expected document structure.

Conclusion

Implementing these steps will streamline your development process and maintain the integrity of your data models. Happy coding!