Records Pagination

A library based on Spring Data pagination

Usage

You must install the dependency using the following command:

npm install records-pagination

Or

yarn add records-pagination

With the library installed you can use the classes Pageable and Page

The Pageable class accepts two parameters

• page [Number]
• limit [Number]

The Page class accepts three parameters

• pageable [Pageable]
• records [T]
• totalRecords [Number]

If you do not enter these parameters when instantiating the class, it will look for it's default values. For page it is 1 and for limit it is 10

An example of use using NestJS

app.controller.ts

import { Controller, Get, ParseIntPipe, Query } from '@nestjs/common';

import { Page, Pageable } from 'records-pagination';

import { AppService } from './app.service';
import { User } from './schemas/user.schema';

@Controller()
export class AppController {
  constructor(private readonly appService: AppService) {}

  @Get()
  async findAll(
    @Query('page', ParseIntPipe) page: number,
    @Query('limit', ParseIntPipe) limit: number,
  ): Promise<Page<User>> {
    const pageable = new Pageable(page, limit);
    return await this.appService.findAll(pageable);
  }
}

In the example above I expect to receive a page and a limit always, if your application is optional don't forget to make the validations.

app.service.ts

import { Injectable } from '@nestjs/common';
import { InjectModel } from '@nestjs/mongoose';

import { Model } from 'mongoose';
import { Page, Pageable } from 'records-pagination';

import { User, UserDocument } from './schemas/user.schema';


@Injectable()
export class AppService {
  constructor(@InjectModel(User.name) private userModel: Model<UserDocument>) {}

  async findAll(pageable: Pageable): Promise<Page<User>> {
    const [totalRecords, records] = await Promise.all([
      this.userModel.countDocuments(),
      this.userModel
        .find()
        .skip((pageable.getPage() - 1) * pageable.getLimit())
        .limit(pageable.getLimit())
        .sort([['name', 1]]),
    ]);

    return new Page<User>(pageable, records, totalRecords);
  }
}

In our service we are consuming a collection of MongoDB users. If you have noticed the Page class, expect to receive a type. This type is used to type records

We have a database with the following user data:

[
  {
    "_id": "607a402d96aa69dde66716c0",
    "name": "Aline"
  },
  {
    "_id": "607a3fd896aa69dde66716ba",
    "name": "Ana"
  },
  {
    "_id": "607a3fca96aa69dde66716b9",
    "name": "André"
  },
  {
    "_id": "607a401396aa69dde66716be",
    "name": "Eduardo"
  },
  {
    "_id": "607a402396aa69dde66716bf",
    "name": "Isaac"
  },
  {
    "_id": "607a403896aa69dde66716c1",
    "name": "Maria"
  },
  {
    "_id": "607a3fe996aa69dde66716bb",
    "name": "Silvana"
  },
  {
    "_id": "607a400796aa69dde66716bd",
    "name": "Vanessa"
  },
  {
    "_id": "607a3ffb96aa69dde66716bc",
    "name": "Vilson"
  }
]

Now, if you call the pagination route by passing a page with the value 2 and a limit with a value 4, we have the following return:

{
  "records": [
    {
      "_id": "607a402396aa69dde66716bf",
      "name": "Isaac"
    },
    {
      "_id": "607a403896aa69dde66716c1",
      "name": "Maria"
    },
    {
      "_id": "607a3fe996aa69dde66716bb",
      "name": "Silvana"
    },
    {
      "_id": "607a400796aa69dde66716bd",
      "name": "Vanessa"
    }
  ],
  "totalPages": 3,
  "currentPage": 2,
  "itemsPerPage": 4,
  "totalRecords": 9
}