Building a Simple Pagination System with NestJS, GraphQL, and React
Pagination is a common problem in data-driven applications. It’s essential to limit the amount of data shown on screen to prevent overwhelming the user and improve performance. In this article, we’ll build a simple pagination system using NestJS, GraphQL, and React.
The Pagination Algorithm
Before diving into the implementation, let’s understand the pagination algorithm. We’ll use a simple query that fetches a list of users with two parameters: take and skip. The take parameter specifies the number of users to retrieve, while the skip parameter specifies the offset from which to start fetching.
Setting up the API with NestJS and GraphQL
We’ll start by setting up a NestJS project with GraphQL. We’ll create a users module with a users resolver and a users service. The users service will handle the business logic of fetching users, while the users resolver will handle the GraphQL queries.
Mongoose Schema Setup
We’ll use Mongoose as our database ORM. We’ll create a user schema with the necessary fields, such as id, firstName, and lastName.
Implementing the Users Service
The users service will have two methods: getCount and findAll. The getCount method will return the total number of users, while the findAll method will fetch a list of users based on the take and skip parameters.
Implementing the Users Resolver
The users resolver will have two queries: count and users. The count query will return the total number of users, while the users query will fetch a list of users based on the take and skip parameters.
Building the React Frontend
We’ll build a simple React frontend to consume the API. We’ll create a Users component that will fetch the list of users and render it. We’ll also create a Pagination component that will handle the pagination logic.
Implementing the Pagination Component
The Pagination component will have two state variables: step and amountToFetch. The step variable will keep track of the current page, while the amountToFetch variable will specify the number of users to fetch per page. We’ll also create a renderedSteps array that will render the pagination buttons.
Putting it all Together
We’ll create an App component that will render the Users component and the Pagination component. We’ll also create an index component that will render the App component and set up the Apollo client.
Conclusion
In this article, we built a simple pagination system using NestJS, GraphQL, and React. We implemented a users service that handles the business logic of fetching users, a users resolver that handles the GraphQL queries, and a Pagination component that handles the pagination logic. We also set up a React frontend to consume the API and render the list of users.