Inserting Documents

Part of the Databases with MongoDB section of Coddy's Node.js journey. Lesson 2 of 18.

A client sends a new book in a POST body, and the server has to store it and say what it stored.

Every document has an _id field, its unique key in the collection. When the object you insert has none, insertOne creates one and also writes it into that same object. The call answers only acknowledged and insertedId, never the document itself.

const movie = { title: 'Alien', year: 1979 };
const result = await movies.insertOne(movie);

console.log(result);    // { acknowledged: true, insertedId: new ObjectId('66f1...') }
console.log(movie._id); // the same id

So after the insert, the object you passed is the stored document, _id included: that is what a client wants back.

Challenge

Easy

POST /books stores the JSON body as a new book.
It answers 201 with the stored book, its _id included.

Send POST /books with { "title": "Beloved", "author": "Toni Morrison", "year": 1987, "isbn": "9781400033416", "genre": "literary" }. Then send GET /books and look at the Data tab.

Try it yourself

import express from 'express';
import { MongoClient } from 'mongodb';

const client = new MongoClient('mongodb://localhost:27017');
const db = client.db('shelf');
const books = db.collection('books');

await books.insertMany([
    { title: 'Dune', author: 'Frank Herbert', year: 1965, isbn: '9780441013593', genre: 'scifi' },
    { title: 'Kindred', author: 'Octavia E. Butler', year: 1979, isbn: '9780807083697', genre: 'scifi' },
    { title: 'Emma', author: 'Jane Austen', year: 1815, isbn: '9780141439587', genre: 'classic' },
]);

const app = express();
app.use(express.json());

// Every error answers { error: message }.
function sendError(res, status, message) {
    res.status(status).json({ error: message });
}

app.get('/', (req, res) => {
    res.send('Bookshelf API');
});

app.get('/books', async (req, res) => {
    const list = await books.find().toArray();
    res.json(list);
});

app.listen(3000, () => {
    console.log('Bookshelf is running on port 3000');
});