Simple Deno API with testing part

Deno is a simple, modern, and secure runtime for JavaScript and TypeScript that uses V8 and is built in Rust. You can look more about Deno on his official website

Steps

1. Install Deno.
2. Create API
3. Run the API with permissions.
4. Test our API

1. Installation

Deno works on macOS, Linux, and Windows. Deno is a single binary executable. It has no external dependencies.

Download and install

deno_install provides convenience scripts to download and install the binary.

Using Shell (macOS and Linux):

$curl -fsSL https://deno.land/x/install/install.sh | sh

Using PowerShell (Windows):

$iwr https://deno.land/x/install/install.ps1 -useb | iex

Deno Update

To update a previously installed version of Deno, you can run:

$deno upgrade

2. CreateAPI

You have to create the project structure first of all it will be simple and easy just navigate to your Desktop and run this command :

$mkdir denoAPi

Open your text editor , and create a file named index.ts or server.ts

we are going to use TYPESCRIPT

import { Application, Router } from 'https://deno.land/x/oak@v4.0.0/mod.ts'

// here we have the default values for the host parameters
const PORT = 8080
const HOST = 'localhost'

// APP and Routes
const app = new Application()
const router = new Router()

// API with only a get method
router.get('/api', (context) => {
  context.response.body = 'Welcome to your first DenoAPI ! Keep it!'
})

// We make the app use the routes
app.use(router.routes())
app.use(router.allowedMethods())

// Run configuration for the app
const HOST_PORT = `${HOST}:${PORT}`
console.log(`Listen on ${HOST_PORT}`)
app.listen(HOST_PORT)

Add this to the index.ts file.

3. Run the API with permissions.

Deno is secure by default. Therefore, unless you specifically enable it, a deno module has no file, network, or environment access for example. Access to security sensitive areas or functions requires the use of permissions to be granted to a deno process on the command line.

For the following example, xxx.ts has been granted read-only access to the file system. It cannot write to it, or perform any other security sensitive functions.

$deno run --allow-read xxx.ts

To run the Our API we need to set the --allow-net flag to use the network protocols in our app. Now, run this script in your path where the index.ts is.

$ deno run --allow-net ./index.ts

4. Test our API

Now we can go to our browser and test the API at http://localhost:8080/api.

It was a very simple example of Deno you have to search more and discover all the features off this new technology.

Enjoy !