Cómo construir paginación de datos API usando Node Express

Node Express es un marco de JavaScript que se puede utilizar para desarrollar una variedad de aplicaciones web. Se puede utilizar para desarrollar API web que pueden ser consumidas por varias aplicaciones cliente (aplicación web o aplicaciones móviles). La paginación de datos debe implementarse en respuestas de API que involucran largas listas de datos. Este artículo le mostrará paso a paso cómo se implementa la paginación de datos en las API de Node Express.

Este ejemplo será sobre una aplicación de noticias.

Paso 1: crea una carpeta vacía llamada newsapp .

$ mkdir newsapp
cd newsapp
$ npm init

$ npm install express --save

$ npm install mongoose --save

const mongoose = require('mongoose')

const mongoose = require('mongoose')
const ArticleSchema = new mongoose.Schema({
   title: { 
    type: String,
    required: true
   },
   content: {
    type: String,
    required: true
 }
})

module.exports = mongoose.model('Article', ArticleSchema)

const mongoose = require('mongoose')
const ArticleSchema = new mongoose.Schema({
   title: { 
    type: String,
    required: true
   },
   content: {
    type: String,
    required: true
 }
})
module.exports = mongoose.model('Article', ArticleSchema)

const express = require('express')
const newsapp = express()
const mongoosedb = require('mongoose')

const article = require('./articles')

mongoose.connect('mongodb://localhost:27017/test', {useNewUrlParser: true, useUnifiedTopology: true});

const db = mongoose.connection
db.once('open', async () => {
  if (await article.countDocuments().exec() > 0) return
Promise.all([
article.create({ title: 'article 1', 
                content: "News content for article 1" }),
article.create({ title: 'article 2', 
                content: "News content for article 2" }),
article.create({ title: 'article 3', 
                content: "News content for article 3" }),
article.create({ title: 'article 4', 
                content: "News content for article 4" }),
article.create({ title: 'article 5', 
                content: "News content for article 5" }),
article.create({ title: 'article 6', 
                content: "News content for article 6" }),
article.create({ title: 'article 7', 
                content: "News content for article 7" }),
article.create({ title: 'article 8', 
                content: "News content for article 8" }),
article.create({ title: 'article 9', 
                content: "News content for article 9" }),
article.create({ title: 'article 10', 
                 content: "News content for article 10" }),
article.create({ title: 'article 11', 
                content: "News content for article 11" }),
article.create({ title: 'article 12', 
                content: "News content for article 12" }),
article.create({ title: 'article 13', 
                content: "News content for article 13" })
]).then(() => console.log('Added Articles'))
})

function paginatedNewsArticles(model) {
   return async (request, response, next) => {
     const querypage = parseInt(request.query.page)
     const querylimit = parseInt(request.query.limit)
}}

const firstIndex = (page - 1) * limit
const lastIndex = page * limit
if (firstIndex > 0) {
      paginatedArticlesList.previous = {
      previouspage: page - 1,
      limit: limit
    }
  }
if (lastIndex < await model.countDocuments().exec()) {
      paginatedArticlesList.next = {
       nextpage: page + 1,
       limit: limit
     }
}

const express = require('express')
const newsapp = express()
const mongoosedb = require('mongoose')
const article = require('./articles')
mongoose.connect('mongodb://localhost/pagination', { useNewUrlParser: true, useUnifiedTopology: true })
const db = mongoose.connection
db.on('error', console.error.bind(console, 'connection error:'));
db.once('open', async () => {
  if (await article.countDocuments().exec() > 0) return
Promise.all([
   article.create({ title: 'article 1', 
                content: "News content for article 1" }),
   article.create({ title: 'article 2', 
                content: "News content for article 2" }),
   article.create({ title: 'article 3', 
                content: "News content for article 3" }),
   article.create({ title: 'article 4', 
                content: "News content for article 4" }),
   article.create({ title: 'article 5', 
                content: "News content for article 5" }),
   article.create({ title: 'article 6', 
                content: "News content for article 6" }),
   article.create({ title: 'article 7', 
                content: "News content for article 7" }),
   article.create({ title: 'article 8', 
                content: "News content for article 8" }),
   article.create({ title: 'article 9', 
                content: "News content for article 9" }),
   article.create({ title: 'article 10', 
                 content: "News content for article 10" }),
   article.create({ title: 'article 11', 
                content: "News content for article 11" }),
   article.create({ title: 'article 12', 
                content: "News content for article 12" }),
   article.create({ title: 'article 13', 
                content: "News content for article 13" })
]).then(() => console.log('Added Articles'))
})
newsapp.get('/article', paginatedNewsArticles(article), (request, response) => {
response.json(response.paginatedResults)
})
function paginatedNewsArticles(model) {
  return async (request, response, next) => {
    const querypage = parseInt(request.query.page)
    const querylimit = parseInt(request.query.limit)
    const firstIndex = (page - 1) * limit
    const lastIndex = page * limit
    const paginatedArticlesList = {}
   if (firstIndex > 0) {
       paginatedArticlesList.previous = {
       previouspage: page - 1,
       limit: limit
     }
   }
   if (lastIndex < await model.countDocuments().exec()) {
       paginatedArticlesList.next = {
       nextpage: page + 1,
       limit: limit
     }
}
try {
   paginatedArticlesList.results = await
   model.find().limit(limit).skip(firstIndex).exec()
   response.paginatedArticles = paginatedArticlesList
   next()
} catch (e) {
   response.status(500).json({ message: e.message })
}
}}
newsapp.listen(3000)

Y ahí lo tenemos. Espero que te haya resultado útil. Volveré con artículos más interesantes. Gracias por leer.

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