Mongose Paginator

Installation

npm i @andrew_l/mongoose-cursor-paginator

import mongoose from 'mongoose';
import mongoosePaginator from 'mongoose-cursor-paginator';

mongoosePaginator(mongoose);

Usage examples

Simple search with catching filter & sort options of original mongoose query.

// Fetch the first page
const firstPage = await Users.find({ role: 'admin' })
    .limit(10)
    .sort({ createdAt: -1 })
    .lean()
    .paginator();

console.log(firstPage);
/* {
  "metadata": {
    "hasNext": true,
    "next": "ldkkZjBhZTViZTQtNzRkNC00YzY2LWI2MWItYjMzYjE0NzQwODI4pFVzZXKBo19pZP-Bo19pZNkkZjBhZTViZTQtNzRkNC00YzY2LWI2MWItYjMzYjE0NzQwODI4gA"
  },
  "items": [
    { doc_1 },
    { doc_n },
    ...
    { doc_10 },
  ]
} */

const secondPage = await Users.find({ role: 'admin' })
    .limit(10)
    // sort can be overwrited by next token
    .sort({ createdAt: -1 })
    .lean()
    .paginator({
        next: firstPage.metadata.next
    });
    
console.log(secondPage);
/* {
  "metadata": {
    "hasNext": false,
    "next": null
  },
  "items": [
    { doc_1 },
    { doc_2 },
    { doc_3 }
  ]
} */

Advanced usage with passing paginator options by hand

import { paginCursor } from 'mongoose-cursor-paginator';

// Make query with some criteria
const firstPage = await searchUsers({
    role: 'admin'
});

// Now we can pass only next cursor and keep the role conditions from previous query
const secondPage = await searchUsers({
    next: firstPage.metadata.next
});

function searchUsers(queryParams) {
    const paginOptions = {
        queryFilter: {},
        queryOptions: {
            sort: { status: 1, createdAt: -1, _id: 1 },
            limit: 10
        },
        // Indicates that we don't wanna to use 'status' as a range condition for next queries
        paginationFields: ['createdAt', '_id'],
        
        // Set current query params as payload for next cursor token
        preQuery: function() {
            this.next.payload = queryParams;
        }
    }
    
    if (queryParams.next) {
        // Handly decode cursor token
        paginOptions.next = paginCursor.decode(queryParams.next);

        // Set payload data as query params from previous request
        queryParams = paginOptions.next.payload;
    }

    // Parse query object and pass into db conditions
    if (typeof queryParams.role === 'string') {
        paginOptions.queryFilter.role = queryParams.role;
    }

     return Users.find()
        .lean()
        .paginator(paginOptions);
}

Stream usage

// Fetch the first page
const dbQuery = await Users.find({ role: 'admin' })
    .limit(10)
    .sort({ createdAt: -1 })
    .lean();

const dbStream = await dbQuery.paginator.stream();

dbStream.on('data', console.log);
dbStream.on('end', () => {
    const metadata = dbQuery.paginator().getMetadata();
    console.log({ metadata });
    /* {
      "metadata": {
        "hasNext": true,
        "next": "ldkkZjBhZTViZTQtNzRkNC00YzY2LWI2MWItYjMzYjE0NzQwODI4pFVzZXKBo19pZP-Bo19pZNkkZjBhZTViZTQtNzRkNC00YzY2LWI2MWItYjMzYjE0NzQwODI4gA"
      }
    */
});

Tips

• The last sorting key must be uniq & sortable (Number, ObjectId has perfect)