koa-”next generation web framework for node.js”

What is koa.js

The designers of Express.js created Koa.js, an open-source, simple, and adaptable Node.js web framework. They refer to Koa.js as the Node.js framework for the next level. Koa.js is described as a leaner, more expressive, and more robust basis for online apps and APIs on its official website. By employing async functions, Koa eliminates callbacks and dramatically improves error management. Although Koa’s core lacks middleware, it does contain an elegant set of tools for rapidly and easily constructing servers.

The usage of ES6 generators is a fundamental aspect of Koa.js, which means a program created with it will have fewer callbacks while employing the asynchronous code we’ve come to know from Node.js behind the scenes. However, the code is obviously different and it is lot shorter.

Characteristics of Koa.js

Koa.js has its own set of features that make it more expressive and developer-friendly. Among the features are:

1. It makes use of ES6 generators.

It is used to ease synchronous programming and to facilitate control flow both upstream and downstream.

2. It’s cutting-edge and futuristic.

It was created using ES6 specs. ES6 makes it easy to develop any sophisticated program by adding numerous new classes and modules. As a result, it assists developers in creating maintainable apps that hold up over time.

3. It takes up little space.

Koa.js has a smaller footprint than other Node.js frameworks. This allows developers to create middleware that is lighter and more efficient. They do, however, have the option of plugging in a number of modules to expand the system to meet the needs of varied projects.

4. Improved Error Handling

Koa.js simplifies and improves error handling by making better use of middleware. The framework’s built-in error catchall helps developers avoid website crashes. Programmers can report errors with a simple ‘try/catch’ command without writing any additional code. Koa.js developers can also customize error handling by simply changing the default configuration.

5. It makes use of a context object.

Koa.js also assists developers in encapsulating the vanilla response and request objects into a single object using Context. The unified object includes a number of handy methods and assessors that make it easy for developers to design web apps and APIs. This context is a NodeJS object that combines the request and response into a single object with multiple methods for developing web apps and APIs.

Now lets write a simple Hello World using koa

Hello World

You must have node.js installed on your computer in order to use koa.js. Type the following code in the terminal to see if Node.js has been installed.

node --version

If this did not return any thing, You have to install node by visiting https://nodejs.org/en/download/

Aight! Lets start the work

Step 1 — We need to open our computer terminal and create a folder and cd in to to

mkdir hello-world
cd hello-world

Step 2 — Use the following command to create the package.json file with npm.

npm init

It will request the following information from you —

package.json configuration

Step 3 — Now we have package.json file setup and lets install koa and add it to our package.json

npm install --save koa

That’s all we need to get started with the Koa framework. We’ll install nodemon from npm to make our development process a lot easier. It automatically restarts our server whenever we make a change to any of our files; otherwise, we must manually restart the server after each file modification. Use the following command to install nodemon.

npm install -g nodemon

Ok now we all done to start our koa work,

Now we have to create app.js fie in root and need to add below lines.

var koa = require('koa');
var app = new koa();app.use(function* (){
   this.body = 'Hello world!';
});
app.listen(3000, function(){
   console.log('Server running on https://localhost:3000')
});

Now our server configurations are done. Lets start the server by entering following command to terminal.

nodemon app.js

Now server is ready and lets open the browser and type this url. https://localhost:3000

Terminal view after running the server

That's all.!😀