NodeJS + Express part 4: CRUD API
Tags: javascript, node, express, beginners
Published: 2021-10-30 11:34:59

---
title: NodeJS + Express part 4: CRUD API
description: 
published: true
tags: javascript, nodejs, express, beginner
cover_image: https://dev-to-uploads.s3.amazonaws.com/uploads/articles/gpbxy1bb1cdkvkabsokk.png
series: expressJS
---

Here is a series of articles that will allow you to create backend applications with NodeJS + Express.

This series is the continuation of my series on the basics of NodeJS. If you don't have basic knowledge of NodeJS read this series first: [Introduction to NodeJS](https://dev.to/ericchapman/create-a-backend-in-javascript-introduction-to-node-js-215a)

Node.js is today a must, so it is essential for a developer to master it.

So I will publish a new article about every two days and little by little you will learn everything there is to know about Node.js + Espress

To not miss anything follow me on twitter: https://twitter.com/EricTheCoder_

<hr>
### CRUD API

Now that we know the basics concept, it's time to build real CRUD API (create, read, update, delete)

We will build all those CRUD routes:

Create: POST /api/products

Read all: GET /api/products

Read: GET /api/product/1

Update: PUT /api/products/1

Delete: DELETE /api/products/1

### Return status
With a CRUD API you can return data but also status code.

Here is a list of some status code and there meaning
```jsx
res.status(200) // Ok
res.status(201) // Created
res.status(204) // No content
res.status(400) // Bad request
res.status(401) // Unauthorized
res.status(403) // Forbidden
res.status(404) // Not found
res.status(500) // Server error
```
### Create a file name data.js and copy/paste this code
```js
const products = [
    { id: 1, name: 'iPhone', price: 800 },
    { id: 2, name: 'iPad', price: 650 },
    { id: 3, name: 'iWatch', price: 750 }
]

module.exports = products
```

### Load data and start the server

```jsx
const express = require('express')
const app = express()
const products = require('./data.js')

app.listen(5000, () => {
    console.log('server is listening on port 5000')
})
```

### Create: POST /api/products

```jsx
app.use(express.json()) // parse json body content

app.post('/api/products', (req, res) => {
    const newProduct = {
        id: products.length + 1,
        name: req.body.name,
        price: req.body.price
    }
    products.push(newProduct)
    res.status(201).json(newProduct)
})
```
The app.use(express.json) is a middleware that take JSON content and create related req.body properties. (ex. req.body.name and req.body.price)

The res.status(201).json(newProduct) set the return response status to 201 (created) and also return the newProduct data in JSON format.

### Read all: GET /api/products
```jsx
app.get('/api/products', (req, res) => {
    res.json(products)
})
```

### Read: GET /api/product/1
```jsx
app.get('/api/products/:productID', (req, res) => {
    const id = Number(req.params.productID)
    const product = products.find(product => product.id === id)
		
    if (!product) {
        return res.status(404).send('Product not found')
    }
    res.json(product)
})
```
As seen in part 2, first we retrieved the productID from the route parameter.

Then we check if this product exist and send a response accordingly.

res.json(product) send the product in JSON format with a 200 ok status code.

### Update: PUT /api/products/1

```jsx
app.use(express.json()) // parse json body content

app.put('/api/products/:productID', (req, res) => {
    const id = Number(req.params.productID)
    const index = products.findIndex(product => product.id === id)
    if (index === -1) {
        return res.status(404).send('Product not found')
    }
    const updatedProduct = {
        id: products[index].id,
        name: req.body.name,
        price: req.body.price
    }
    products[index] = updatedProduct
    res.status(200).json('Product updated')
})
```

### Delete: DELETE /api/products/1

```jsx
app.use(express.json()) // parse json body content

app.delete('/api/products/:productID', (req, res) => {
    const id = Number(req.params.productID)
    const index = products.findIndex(product => product.id === id)
		if (index === -1) {
        return res.status(404).send('Product not found')
    }
    products.splice(index,1)
    res.status(200).json('Product deleted')
})
```

## Conclusion
That's all for today, follow me on twitter: https://twitter.com/EricTheCoder_ to be notified of the publication of the next article (within two days).