July 18 2019

React + Node - Server Side Pagination Tutorial & Example

Example built with React 16.8.6

Other versions available:

This is a simple example of how to implement server-side pagination in React with a Node.js backend API.

The example contains a hard coded array of 150 objects split into 30 pages (5 items per page) to demonstrate how the pagination logic works. Styling of the example is done with Bootstap 4.

The tutorial code is available on GitHub at https://github.com/cornflourblue/react-node-server-side-pagination.

Here it is in action (may take a few seconds for the container to startup): (See on CodeSandbox at https://codesandbox.io/s/react-node-server-side-pagination-example-j5c1w)


Running the React + Node Pagination Example Locally

  1. Install NodeJS and NPM from https://nodejs.org.
  2. Download or clone the tutorial project source code from https://github.com/cornflourblue/react-node-server-side-pagination.
  3. Install required npm packages of the backend Node API by running the npm install command in the /server folder.
  4. Start the backend Node API by running npm start in the /server folder, this will start the API on the URL http://localhost:4000.
  5. Install required npm packages of the frontend React app by running the npm install command in the /client folder.
  6. Start the React frontend app by running npm start in the /client folder, this will build the app with webpack and automatically launch it in a browser on the URL http://localhost:8080.


Server-Side (Node.js) Pagination Logic

Pagination is handled by the backend Node API with the help of the jw-paginate npm package, for more info on how the pagination logic works see JavaScript - Pure Pagination Logic in Vanilla JS / TypeScript.

Below is the code for the paged items route (/api/items) in the node server file (/server/server.js) in the example, it creates a hardcoded list of 150 items to be paged, in a real application you would replace this with real data (e.g. from a database). The route accepts an optional page parameter in the url query string, if the parameter isn't set it defaults to the first page.

The paginate() function is from the jw-paginate package and accepts the following parameters:

  • totalItems (required) - the total number of items to be paged
  • currentPage (optional) - the current active page, defaults to the first page
  • pageSize (optional) - the number of items per page, defaults to 10
  • maxPages (optional) - the maximum number of page navigation links to display, defaults to 10

The output of the paginate function is a pager object containing all the information needed to get the current pageOfItems out of the items array, and to display the pagination controls in the React frontend, including:

  • startIndex - the index of the first item of the current page (e.g. 0)
  • endIndex - the index of the last item of the current page (e.g. 9)
  • pages - the array of page numbers to display (e.g. [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 ])
  • currentPage - the current active page (e.g. 1)
  • totalPages - the total number of pages (e.g. 30)

I've set the pageSize to 5 in the CodeSandbox example above so the pagination links aren't hidden below the terminal console when the container starts up. In the code on GitHub I didn't set the page size so the default 10 items are displayed per page in that version.

The current pageOfItems is extracted from the items array using the startIndex and endIndex from the pager object. The route then returns the pager object and current page of items in a JSON response.

// paged items route
app.get('/api/items', (req, res, next) => {
    // example array of 150 items to be paged
    const items = [...Array(150).keys()].map(i => ({ id: (i + 1), name: 'Item ' + (i + 1) }));

    // get page from query params or default to first page
    const page = parseInt(req.query.page) || 1;

    // get pager object for specified page
    const pageSize = 5;
    const pager = paginate(items.length, page, pageSize);

    // get page of items from items array
    const pageOfItems = items.slice(pager.startIndex, pager.endIndex + 1);

    // return pager object and current page of items
    return res.json({ pager, pageOfItems });
});


Client-Side (React) Pagination Component

Since the pagination logic is handled on the server, the only thing the React client needs to do is fetch the pager information and current page of items from the backend, and display them to the user.

React Home Page Component

Below is the React home page component (/client/src/HomePage/HomePage.jsx) from the example. The loadPage() method determines the current page by checking for the value in the url query params or defaulting to page 1, then fetches the pager object and pageOfItems for the current page from the backend API with an HTTP request.

The componentDidMount() React lifecycle hook kicks off the first call to loadPage() when the React component loads, then the componentDidUpdate() React lifecycle hook calls loadPage() when the page is changed with the pagination links.

The component renders the current page of items as a list of divs, and renders the pagination controls using the data from the pager object. Each pagination link sets the page query parameter in the url using the Link React Router component with the search parameter.

The CSS classes used are all part of Bootstrap 4.3, for more info see https://getbootstrap.com/docs/4.3/getting-started/introduction/.

import React from 'react';
import { Link } from 'react-router-dom';

class HomePage extends React.Component {
    constructor(props) {
        super(props);

        this.state = {
            pager: {},
            pageOfItems: []
        };
    }

    componentDidMount() {
        this.loadPage();
    }

    componentDidUpdate() {
        this.loadPage();
    }

    loadPage() {
        // get page of items from api
        const params = new URLSearchParams(location.search);
        const page = parseInt(params.get('page')) || 1;
        if (page !== this.state.pager.currentPage) {
            fetch(`/api/items?page=${page}`, { method: 'GET' })
                .then(response => response.json())
                .then(({pager, pageOfItems}) => {
                    this.setState({ pager, pageOfItems });
                });
        }
    }

    render() {
        const { pager, pageOfItems } = this.state;
        return (
            <div className="card text-center m-3">
                <h3 className="card-header">React + Node - Server Side Pagination Example</h3>
                <div className="card-body">
                    {pageOfItems.map(item =>
                        <div key={item.id}>{item.name}</div>
                    )}
                </div>
                <div className="card-footer pb-0 pt-3">
                    {pager.pages && pager.pages.length &&
                        <ul className="pagination">
                            <li className={`page-item first-item ${pager.currentPage === 1 ? 'disabled' : ''}`}>
                                <Link to={{ search: `?page=1` }} className="page-link">First</Link>
                            </li>
                            <li className={`page-item previous-item ${pager.currentPage === 1 ? 'disabled' : ''}`}>
                                <Link to={{ search: `?page=${pager.currentPage - 1}` }} className="page-link">Previous</Link>
                            </li>
                            {pager.pages.map(page =>
                                <li key={page} className={`page-item number-item ${pager.currentPage === page ? 'active' : ''}`}>
                                    <Link to={{ search: `?page=${page}` }} className="page-link">{page}</Link>
                                </li>
                            )}
                            <li className={`page-item next-item ${pager.currentPage === pager.totalPages ? 'disabled' : ''}`}>
                                <Link to={{ search: `?page=${pager.currentPage + 1}` }} className="page-link">Next</Link>
                            </li>
                            <li className={`page-item last-item ${pager.currentPage === pager.totalPages ? 'disabled' : ''}`}>
                                <Link to={{ search: `?page=${pager.totalPages}` }} className="page-link">Last</Link>
                            </li>
                        </ul>
                    }                    
                </div>
            </div>
        );
    }
}

export { HomePage };

 

Subscribe or Follow Me For Updates

Subscribe to my YouTube channel or follow me on Twitter or GitHub to be notified when I post new content.

 


Sponsored by