Comment créer une pagination de données API à l'aide de Node Express

Node Express est un framework JavaScript qui peut être utilisé pour développer une variété d'applications Web. Il peut être utilisé pour développer des API Web pouvant être utilisées par diverses applications clientes (application Web ou applications mobiles). La pagination des données doit être implémentée sur les réponses API qui impliquent de longues listes de données. Cet article vous montrera étape par étape comment la pagination des données est implémentée dans les API Node Express.

Cet exemple concerne une application d'actualités.

Étape 1 : Créez un dossier vide appelé 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)

Et là, nous l'avons. J'espère que vous avez trouvé cela utile. Je reviendrai avec des articles plus intéressants. Merci pour la lecture.

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