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How to create a basic API in NodeJS

In this post I’m going to show you how easy it is to create a basic API using Node JS and connect it to a MongoDB instance with automated tests (Test).

Tools I plan on using

  • NodeJS
  • Express
  • JEST
  • MongoDB

Creating a basic project

$ mkdir todo
$ cd todo

Initialise a new node app

$ npm init

Install express

$ npm install express —-save

Create an empty app

$ touch app.js

Update app.js

const express = require('express');

// Set up the express app
const app = express();

const todos =  [
    {
      id: 1,
      title: "lunch",
      description: "Go for lunch by 2pm"
    }
];

// get all todos
app.get('/api/v1/todos', (req, res) => {
  res.status(200).send({
    message: 'Hi John, Here are your todos. You better start doing some work! ;)',
    todos: todos
  })
});
const PORT = 3000;

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

Run the app

$ node app.js

Go to URL: http://localhost:3000/api/v1/todos

Connect to a mongo DB

Open up a new terminal tab

Install mongod

$ brew install mongodb

Run the DB

$ mongod --config /usr/local/etc/mongod.conf

Go back to the other window and install Mongoose

$ npm install mongoose --save

Mongoose is Nodejs package for modeling Mongodb. It helps you handle validation and business logic for mongodb on Nodejs.

Add in mongoose dependancy to app.js

// Import Body parser
const bodyParser = require('body-parser');

// Import Mongoose
const mongoose = require('mongoose');

// Configure bodyparser to handle post requests
app.use(bodyParser.urlencoded({
   extended: true
}));

app.use(bodyParser.json());

// Connect to Mongoose and set connection variable
mongoose.connect('mongodb://localhost/todos');
const db = mongoose.connection;

Create a GET todo endpoint

Create a controller

In this controller all we want to do is get all ToDo items that exist in the DataBase.

Create a folder called contollers

$ mkdir contollers

Inside of the models directory create a file called todoController.js

// todoController.js

// Import ToDo model
const ToDo = require('./../model/todoModel');

// View all ToDo items
exports.findAll = (req, res) => {
    ToDo.find()
    .then(todos => {
        res.send(todos);
    }).catch(err => {
        res.status(500).send({
            message: err.message || "Some error occurred while retrieving products."
        });
    });
};

Create a model

In here we want to create a model of our ToDos and create a schema for it.

Create a folder called contollers

$ mkdir models

Inside of the models directory create a file called TodoModel.js

// TodoModel.js
const mongoose = require('mongoose');

// Setup schema
const toDoSchema = mongoose.Schema({
      title: {
        type: String,
        required: true
    },
        description: {
        type: String,
        required: true
    }
});

module.exports = mongoose.model('todo', toDoSchema);

Update the route

Remove the old get function and replace with this

const todoController = require('./controllers/todoController.js');

app.get('/api/v1/todos', todoController.findAll);

Create a new todo

Inside your controller.js add in the following

exports.create = (req, res) => {
    // Create a Product
    const todo = new ToDo({
        title: req.body.title,
        description: req.body.description,
    });

    // Save Product in the database
    todo.save()
    .then(data => {
        res.send(data);
    }).catch(err => {
        res.status(500).send({
            message: err.message || "Some error occurred while creating the ToDo item."
        });
    });
};

Create an endpoint to post data to it.

Inside your app.js add in the following

// Post a todo item
app.post('/api/v1/todo', todoController.create);

Final files.

todoController.js

// Import contact model
const ToDo = require('./../model/todoModel');

// View all ToDo items
exports.findAll = (req, res) => {
    ToDo.find()
    .then(todos => {
        res.send(todos);
    }).catch(err => {
        res.status(500).send({
            message: err.message || "Some error occurred while retrieving products."
        });
    });
};

exports.create = (req, res) => {
    // Create a Product
    const todo = new ToDo({
        title: req.body.title,
        description: req.body.description,
    });

    // Save Product in the database
    todo.save()
    .then(data => {
        res.send(data);
    }).catch(err => {
        res.status(500).send({
            message: err.message || "Some error occurred while creating the ToDo item."
        });
    });
};

todoModel.js

// TodoModel.js
const mongoose = require('mongoose');

// Setup schema
const toDoSchema = mongoose.Schema({
      title: {
        type: String,
        required: true
    },
        description: {
        type: String,
        required: true
    }
});

module.exports = mongoose.model('todo', toDoSchema);

POST to the todo api

{
	"title": "lunch",
	"description": "Go for lunch by 2pm"
}

Verify by hitting the endpoint.

http://localhost:3000/api/v1/todos

Published 10 Jul 2019

My life as a software development managerJohn Wakeling on Twitter