Pagination and filtering are essential techniques for handling large datasets in an API. In GraphQL, these techniques allow clients to request exactly the data they need efficiently. In this chapter, we will learn how to implement pagination and filtering in our GraphQL API.

Pagination

Pagination divides large datasets into manageable parts, making data transfer and manipulation easier. In GraphQL, there are several ways to implement pagination. In this example, we will use limit-offset based pagination.

Defining Schema for Pagination

We will add limit and offset arguments to our book query.

Schema (schema.js):

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Implementing Resolvers for Pagination

We will update the corresponding resolver to handle limit and offset.

Resolvers (resolvers.js):

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Pagination Example in GraphiQL

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Filtering

Filtering allows clients to obtain a specific subset of data based on certain criteria.

Defining Schema for Filtering

We will add authorId and publishedYear arguments to our book query to allow filtering.

Schema (schema.js):

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Implementing Resolvers for Filtering

We will update the books resolver to handle the filters.

Resolvers (resolvers.js):

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Filtering Example in GraphiQL

• Filtering by author:

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• Filtering by published year:

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Combining Pagination and Filtering

You can combine pagination and filtering to obtain finer control over the requested data.

Combined Example in GraphiQL

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Summary

In this chapter, we learned how to implement pagination and filtering in a GraphQL API. We covered:

• Definition of limit and offset arguments for pagination.
• Implementation of filters using additional arguments.
• Combining pagination and filtering for even more precise queries.

These techniques will allow you to efficiently handle large datasets and provide clients the ability to request exact data based on their needs.

[Placeholder: Diagram showing the flow of a GraphQL query with pagination and filtering, from client request to the server response]

In the next chapter, we will explore how to handle errors in GraphQL effectively.