express-mongoose-pagination: A TypeScript repository from gocodecraving

Introduction

Hello Folks,

Pagination of data is highly recommended if you want to fetch large number of records from the collection. For eg: All users from Users collection. If you fetch the records without pagination, it may result in slow performance at both back-end and front-end side.

So, this tool will help you to paginate your data without impacting the performance.

You need to use this tool with find() query method of mongoose ODM to make it work.

You just need to pass the request object, and some optional parameters to the paginate() method of this tool, it will return an object with useful information that you can use to handle you data with ease.

I have explained it's implementation below:

Installation

Install with the following command

npm i express-mongoose-pagination or npm install express-mongoose-pagination

Implementation

1. Import the module in model

//UserModel.js

const pagination = require('express-mongoose-pagination')

or

//ES6+
import pagination from 'express-mongoose-pagination'

2. Apply as plugin to your Schema Instance

//UserModel.js

const userSchema = new Schema({...})

userSchema.plugin(pagination)

module.exports = mongoose.model('User', userSchema)

or

//ES6+
export default mongoose.model('User', userSchema)

3. Somewhere inside your routes block

//routes.js
const User = require('../models/UserModel.js')

or

import User from '../models/UserModel.js'

//Users route get request
app.get('/users', async function(req, res){

   //1. Use the find query method normally without any restrictions. You can pass all available parameters like condition, projection, options, etc

   const users = await User.find().paginate(req, { withQueryString: true })

   res.render('views/users.html', { users }) //render and pass users

})

That's It

Data Object and Query Parameters

You will get the output data in the form of object as mentioned below:

//console.log(users)

{
   currentPage: 1// Current page number,
   data: [
      {_id:1, name:'User 1', email: 'user1@test.com'},
      {...},
      {...},
      .
      .
      .
      //upto 15 records

   ] // Array of data objects,
   firstPageUrl: 'https://xyz.com/users?page=1',
   lastPageUrl: 'https://xyz.com/users?page=4',
   lastPage: 4 // Last page number,
   nextPageUrl: 'https://xyz.com/users?page=2',
   prevPageUrl: null,
   path: 'https://xyz.com/users',
   perPage: 15 //Per page value,
   total: 60 //Total matched records in users collection
}

//If there is no records you will get same object format with changed values and most of them will be null or empty array for data field.

Pre-defined parameters:

Parameter	Usage	Default Value	Is Required	Data Type
page	Navigation between pages	1	No	Int/Number
perPage	Number of Records per page	15	No	Int/Number

Custom parameters:

You can pass n number of query parameters with your endpoint and that will reflect in all url specific fields except path field.

Note: By default custom query string option is disabled, you can enable it by passing withQueryString as a boolean value

//pass withQueryString option like this

const users = await User.find({ sortIndex: {$gt: 10 } })
                .sort({ sortIndex: 1 })
                .paginate(request, { withQueryString:true })

// Output will be like this
{
   currentPage:1,
   .
   .
   firstPageUrl: 'https://xyz.com/users?page=1&perPage=10&foo=bar&john=doe',
   lastPageUrl: 'https://xyz.com/users?page=4&perPage=10&foo=bar&john=doe',
   .
   .

}

Serial Numbers:

You can pass _sno as boolean to options parameters object to paginate function to get data with serial numbers.

//pass _sno option like this

const users = await User.find({ sortIndex: {$gt: 10 } })
                .sort({ sortIndex: 1 })
                .paginate(request, { withQueryString:true, _sno:true })

// Output will be like this
{
   currentPage:1,
   data:[
      {
         ...
         ...
         _sno: 1
      },
      {
         ...
         ...
         _sno: 2
      }
      ....
   ]
   .
   firstPageUrl: 'https://xyz.com/users?page=1&perPage=10&foo=bar&john=doe',
   lastPageUrl: 'https://xyz.com/users?page=4&perPage=10&foo=bar&john=doe',
   .
   .

}

License

MIT

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