Implementing Pagination for Your REST API with MongoDB and Express.js

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Understanding the Problem

Imagine you have four different collections in your MongoDB database: mixed, organic, upcycle, and vegan. All collections share similar attributes, allowing for organized management of data.

Your initial task involved retrieving data from these collections while ensuring you can paginate the results. Initially, implementing simple REST API endpoints was straightforward; however, adding pagination into the mix requires a more thoughtful approach.

The Solution: Implementing Pagination in Your API

To add pagination to your existing API endpoint, follow along with the revised code structure. Below, we’ll break down each crucial part of the implementation:

1. Setting the API Route

First, update your API route to accommodate a page parameter, which allows for flexibility in pagination:

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This modification creates a new endpoint that will enable requesting different pages of data.

2. Defining Pagination Parameters

Next, specify the pagination parameters, such as the page and the limit. In this case, we will make limit a constant value, ensuring that only a fixed number of items are returned per page:

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

3. Aggregating Data from Collections

In this step, aggregate data from each collection while filtering for "not sold out" items. Utilize the $match and $project pipeline stages to ensure you only retrieve the relevant data.

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4. Collecting and Paginating Data

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5. Sending the Response

Finally, ensure your API returns the paginated results effectively, providing both the count of items on the current page and the items themselves.

Conclusion

If you have further suggestions or more efficient methods, feel free to reach out or leave a comment below!