paginate-nodejs

This repository contains two pagination functions for Mongoose models: paginateWithOffset and paginateWithCursor. These functions allow you to easily implement offset-based and cursor-based pagination in your Node.js and Mongoose projects.

Table of Contents

• Installation
• Usage
• Contributing

Installation

To use these pagination functions, you can install the paginate-nodejs package as a dependency. Additionally, make sure you have mongoose installed if you haven't already:

• mongoose: An Object Data Modeling (ODM) library for MongoDB.

npm install paginate-nodejs mongoose 

Usage

Offset Pagination (paginateWithOffset)

Offset pagination is a common pagination method where you specify the page number and the number of results per page. This function provides options to sort the results by a specific field and in a specific direction.

/**
 * Offset pagination function for Mongoose models.
 * @param {mongoose.Model} Model - The Mongoose model to paginate.
 * @param {Object} [filter] - Optional filter conditions.
 * @param {Object} [options] - Pagination options.
 * @param {number} [options.page=1] - The current page number (default is 1).
 * @param {number} [options.perPage=10] - Number of results per page (default is 10).
 * @param {string} [options.sortField] - The field to sort results by.
 * @param {number} [options.sortDirection=1] - Sort direction (1 for ascending, -1 for descending).
 * @returns {Promise<Object>} - An object containing paginated results and metadata.
 */
const { paginateWithOffset } = require('paginate-nodejs');
app.get('/offset-paginate', async (req, res) => {
    try {
        const { page = 1, perPage = 2, sortField = 'age', sortDirection = 1 } = req.query;

        const parsedPage = parseInt(page) || 1;
        const parsedPerPage = parseInt(perPage) || 2;
        const parsedSortDirection = parseInt(sortDirection) || 1;

        const paginationOptions = {
            page: parsedPage,
            perPage: parsedPerPage,
            sortField,
            sortDirection: parsedSortDirection,
        };

        const result = await paginateWithOffset(Model, {}, paginationOptions);

        res.json(result);
    } catch (err) {
        console.error(err);
        res.status(500).json({ error: 'Internal Server Error' });
    }
});

/**
 * Offset pagination - cURL
 * http://localhost:3000/offset-paginate?page=1&perPage=10&sortField=age&sortDirection=1
**/

Cursor Pagination (paginateWithCursor)

Cursor pagination is a more efficient method for large datasets. It uses a cursor (usually the ID of the last item from the previous page) to fetch the next set of results.

/**
 * Cursor-based pagination function for Mongoose models.
 * @param {mongoose.Model} model - The Mongoose model to paginate.
 * @param {Object} query - Optional query conditions.
 * @param {string} cursor - The cursor representing the last record in the previous page.
 * @param {number} pageSize - Number of results per page.
 * @returns {Promise<Object>} - An object containing paginated results and metadata.
 */
const { paginateWithCursor } = require('paginate-nodejs');
app.get('/cursor-paginate', async (req, res) => {
    try {
        const { cursor, limit } = req.query;
        const pageSize = parseInt(limit) || 5;

        const query = {};
        const result = await paginateWithCursor(Model, query, cursor, pageSize);
        res.json(result);
    } catch (error) {
        console.error(error);
        res.status(500).json({ error: 'Internal Server Error' });
    }
});

/**
 * Cursor pagination - cURL
 * http://localhost:3000/paginate?cursor=`${next}` // replace next with value of the next in response
**/

Contributing

Contributions to paginate-nodejs are welcome! If you'd like to contribute to this project, please follow these steps:

1. Fork the repository.
2. Create a new branch for your feature or bug fix: git checkout -b feature/your-feature-name.
3. Commit your changes: git commit -m "Add your feature or fix".
4. Push your branch to your fork: git push origin feature/your-feature-name.
5. Create a pull request on the original repository.

Please follow the Code of Conduct and Contributing Guidelines when contributing.