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Working with MongoDB

Connecting to Database​

Production​

  • Install mongoose npm i mongoose
app.js
const MONGO_URI = "mongodb://localhost:27017/express-demo"

mongoose.connect(
    MONGO_URI,
    { useNewUrlParser: true, useUnifiedTopology: true },
    () => console.log("Connected to DB")
);

Development​

  • Use In-Memory MongoDB as a devDependency
  • npm i -D mongodb-memory-server
app.ts
import express from 'express';
import mongoose from 'mongoose';

// Routes
app.get("/", (req, res) => {
    res.send("Hello World!");
});

import { MongoMemoryServer } from 'mongodb-memory-server';

const mongoServer = new MongoMemoryServer();

mongoose.Promise = Promise;
mongoServer.getUri().then((mongoUri) => {
  const mongooseOpts = {
    useNewUrlParser: true,
    useUnifiedTopology: true
  };

  mongoose.connect(mongoUri, mongooseOpts, () => {
    console.log(`MongoDB successfully connected to ${mongoUri}`);
  });
});

const PORT = process.env.PORT || 3000;

app.listen(PORT, () => console.log(`Listening on port ${PORT}`));

Defining Schema​

  • Create folder models/
  • Create file Article.js
Article.js
const mongoose = require("mongoose");

const Schema = mongoose.Schema;

const ArticleSchema = new Schema({
    title: {
        type: String,
        required: true,
    },
    description: String,
    date: {
        type: Date,
        default: Date.now,
    },
});

module.exports = mongoose.model("Article", ArticleSchema);

Save data to database​

  • To deal with json and forms add middleware to app.js
app.js
app.use(express.json())

app.use(express.urlencoded({ extended: false }));
  • Add post request route to routes/article.js
  • Use res.json() to return a json

Using new Model()​

article.js
router.post("/", (req, res) => {
    const article = new Article(req.body);
    article.save()
        .then(data => {
            res.json(data)
        }).catch(err => {
            res.status(404).json({message: err})
        })
});
  • OR use JavaScript async await
article.js
router.post("/", async (req, res) => {
    const article = new Article(req.body);

    try {
        const savedArticle = await article.save();
        res.json(savedArticle);
    } catch (err){
        res.status(404).json({ message: err });
    }
});

Using Model.create()​

article.js
router.post("/", async (req, res) => {

    try {
        const savedArticle = Article.create(req.body);
        res.json(savedArticle);
    } catch (err){
        res.status(404).json({ message: err });
    }
});

Get data from database​

All​

article.js
router.get("/", async (req, res) => {
    try {
        const articles = await Article.find();
        res.json(articles);
    } catch (err){
        res.status(404).json({ message: err });
    }
});

Specific​

article.js
router.get("/:id", async (req, res) => {
    try {
        const article = await Article.findById(req.params.id);
        if (!article) {
            throw "Article not found!";
        }
        res.json(article);
    } catch (err) {
        res.status(404).json({ message: err });
    }
});

Update data​

article.js
router.put("/:id", async (req, res) => {
    try {
        const updatedArticle = await Article.updateOne(
            { _id: req.params.id },
            { $set: req.body }
        );

        if (updatedArticle.n == 0) {
            throw "Article not found!";
        }
        const article = await Article.findById(req.params.id)
        res.json(article);
    } catch (err) {
        res.status(404).json({ message: err });
    }
});

Delete data​

article.js
router.delete("/:id", async (req, res) => {
    try {
        const removedArticle = await Article.deleteOne({ _id: req.params.id });
        if (removedArticle.deletedCount == 0) {
            throw "Article not found!";
        }
        res.json(removedArticle);
    } catch (err) {
        res.status(404).json({ message: err });
    }
});