koa-router

What is koa-router?

koa-router is a powerful routing middleware for Koa, a next-generation web framework for Node.js. It allows you to define routes for your web application, handle HTTP methods, and manage middleware in a clean and organized manner.

What are koa-router's main functionalities?

Basic Routing

This code demonstrates how to set up a basic route using koa-router. When a GET request is made to the root URL '/', it responds with 'Hello World!'.

const Koa = require('koa');
const Router = require('koa-router');

const app = new Koa();
const router = new Router();

router.get('/', (ctx, next) => {
  ctx.body = 'Hello World!';
});

app.use(router.routes());
app.use(router.allowedMethods());

app.listen(3000);

Route Parameters

This code demonstrates how to use route parameters with koa-router. When a GET request is made to '/users/:id', it responds with the user ID provided in the URL.

const Koa = require('koa');
const Router = require('koa-router');

const app = new Koa();
const router = new Router();

router.get('/users/:id', (ctx, next) => {
  const userId = ctx.params.id;
  ctx.body = `User ID: ${userId}`;
});

app.use(router.routes());
app.use(router.allowedMethods());

app.listen(3000);

Middleware

This code demonstrates how to use middleware with koa-router. The logger middleware logs the HTTP method and URL of each request before passing control to the next middleware or route handler.

const Koa = require('koa');
const Router = require('koa-router');

const app = new Koa();
const router = new Router();

const logger = async (ctx, next) => {
  console.log(`${ctx.method} ${ctx.url}`);
  await next();
};

router.get('/', logger, (ctx, next) => {
  ctx.body = 'Hello World!';
});

app.use(router.routes());
app.use(router.allowedMethods());

app.listen(3000);

Nested Routes

This code demonstrates how to create nested routes with koa-router. The nestedRouter handles requests to '/nested/info' and responds with 'Nested Route Info'.

const Koa = require('koa');
const Router = require('koa-router');

const app = new Koa();
const router = new Router();
const nestedRouter = new Router();

nestedRouter.get('/info', (ctx, next) => {
  ctx.body = 'Nested Route Info';
});

router.use('/nested', nestedRouter.routes(), nestedRouter.allowedMethods());

app.use(router.routes());
app.use(router.allowedMethods());

app.listen(3000);

Other packages similar to koa-router

express

Express is a fast, unopinionated, minimalist web framework for Node.js. It provides robust routing capabilities similar to koa-router but is more widely used and has a larger ecosystem of middleware and plugins.

hapi

Hapi is a rich framework for building applications and services. It provides powerful configuration-based routing and extensive support for building scalable and maintainable applications. Compared to koa-router, Hapi offers more built-in features and a more opinionated structure.

restify

Restify is a framework specifically designed for building RESTful web services. It provides a similar routing mechanism to koa-router but is optimized for building APIs with a focus on performance and scalability.

README

@koa/router

Router middleware for Koa. Maintained by Forward Email and Lad.

Table of Contents

• Features
• Migrating to 7 / Koa 2
• Install
• Typescript Support
• API Reference
• Contributors
• License

Features

• Express-style routing (app.get, app.put, app.post, etc.)
• Named URL parameters
• Named routes with URL generation
• Match routes with specific host
• Responds to OPTIONS requests with allowed methods
• Support for 405 Method Not Allowed and 501 Not Implemented
• Multiple route middleware
• Multiple and nestable routers
• async/await support

Migrating to 7 / Koa 2

• The API has changed to match the new promise-based middleware signature of koa 2. See the koa 2.x readme for more information.
• Middleware is now always run in the order declared by .use() (or .get(), etc.), which matches Express 4 API.

Install

npm:

npm install @koa/router

Typescript Support

npm install --save-dev @types/koa__router

API Reference

See API Reference for more documentation.

Contributors

Name
Alex Mingoia
@koajs

License

MIT © Alex Mingoia