The Very Simple Router (vs-router) is:

• a router library for the browser
• very small (<2kB gzipped)
• very fast
• synchronous
• event-based
• framework-agnostic
• really very simple

Installation

npm install --save vs-router

// or for yarn:
yarn add vs-router

Usage

import { createRouter } from 'vs-router';

const router = createRouter('/', {
  users: '/users',
  user: '/users/:id'
});

router.addListener('transition', logTransition);

function logTransition({ last, next }) {
  console.log(`Last: ${JSON.stringify(last)}`);
  console.log(`Next: ${JSON.stringify(next)}`);
}


// go to the users route
router.navigate('users');

/*
console output:

Last: { name: 'root', params: null }
Next: { name: 'users', params: null }
*/

router.navigate('user', { id: 1 });

/*
console output:

Last: { name: 'users', params: null }
Next: { name: 'user', params: { id: 1 } }
*/

router.back();

/*
console output:

Last: { name: 'root', params: null }
Next: { name: 'users', params: null }
*/

router.forward();

/*
console output:

Last: { name: 'users', params: null }
Next: { name: 'user', params: { id: 1 } }
*/

router.go(-1);

/*
console output:

Last: { name: 'root', params: null }
Next: { name: 'users', params: null }
*/

Removing listeners

router.removeListener('transition', logTransition);

Destroying the router

router.destroy();

root route

The root path is added automatically, according to the first parameter passed to createRouter. Transitioning back to the root therefore:

router.navigate('root');

The notFound route

A notFound route is added automatically and defaults to /404. In order to override it, register a new root with the notFound name:

const router = createRouter('/', {
  notFound: '/my-not-found-page',
});

Registering new routes

New routes can be added, by passing a name and path pattern:

router.register('userPosts', '/posts/:userId');
router.navigate('userPosts', { userId: 1 }); // works!

Patterns API

URL parameters:

Pattern: /posts/:user
Params:  { user: 'admin' }
Path:    /posts/admin

Pattern: /posts/:user/:tag
Params:  { user: 'admin', tag: 'important' }
Path:    /posts/admin/important

Query parameters:

Pattern: /posts?page=:page
Params:  { page: 1 }
Path:    /posts?page=1

Hash:

Pattern: /posts#:section
Params:  { section: 'comments' }
Path:    /posts#comments

Optional query parameters

Pattern: /posts?page?=:page
Params:  {} // or { page: null }
Path:    /posts

List parameters

Pattern: /posts?id*=:ids
Params:  { ids: [1, 2] }
Path:    /posts?id=1&id=2

Regex can also be used for the patern, so for advanced usage, see the tests.

Credit

The parser is a fork of the excellent teki URL parsing library by Philip Nilsson. It's the beating heart of very-simple-router and is essentially what allows it to stay small and very, very fast.