Grapnel

The first (started in 2010!) Client/Server-Side JavaScript Router with Named Parameters, HTML5 pushState, and Middleware support.

Download/Installation

Download Source:

• Production
• Development

Install with npm

npm install grapnel

Or by using bower:

bower install grapnel

Server only: (with HTTP methods added, more info)

npm install grapnel-server

Grapnel Features

• Supports routing using pushState or hashchange concurrently
• Supports Named Parameters similar to Express, Sinatra, and Restify
• Middleware Support
• Works on the client or server side
• RegExp Support
• Supports # or #! for hashchange routing
• Unobtrusive, supports multiple routers on the same page
• No dependencies

Basic Router

const router = new Grapnel();

router.get('products/:category/:id?', function(req) {
    let id = req.params.id;
    let category = req.params.category;
    // GET http://mysite.com/#products/widgets/134
    console.log(category, id);
    // => widgets 134
});

Using HTML5 pushState

const router = new Grapnel({ pushState : true });

router.get('/products/:category/:id?', function(req) {
    let id = req.params.id;
    let category = req.params.category;

    console.log(category, id);
});

router.navigate('/products/widgets/134');
// => widgets 134

Named Parameters

Grapnel supports regex style routes similar to Sinatra, Restify, and Express. The properties are mapped to the parameters in the request.

router.get('products/:id?', function(req) {
    // GET /file.html#products/134
    console.log(req.params.id);
    // => 134
});

router.get('products/*', function(req) {
    // The wildcard/asterisk will match anything after that point in the URL
    // Parameters are provided req.params using req.params[n], where n is the nth capture
});

Middleware Support

Grapnel also supports middleware:

let auth = function(req, event, next) {
    user.auth(function(err) {
        req.user = this;
        next();
    });
}

router.get('/*', auth, function(req) {
    console.log(req.user);
});

Route Context

You can add context to a route and even use it with middleware:

let usersRoute = router.context('/user/:id', getUser, getFollowers); // Middleware can be used here

usersRoute('/', function(req, event) {
    console.log('Profile', req.params.id);
});

usersRoute('/followers', otherMiddleware, function(req, event) { // Middleware can be used here too
    console.log('Followers', req.params.id);
});

router.navigate('/user/13589');
// => Profile 13589

router.navigate('/user/13589/followers');
// => Followers 13589

Works as a server-side router

import { createServer } from 'http';
import Grapnel from 'grapnel';
const app = new Grapnel();

app.get('/', function(req, route) {
    route.res.end('Hello World!', 200);
});

createServer(function(req, res) {
    app.once('match', function(route) {
        route.res = res;
    }).navigate(req.url);
}).listen(3000);

This is now simplified as a separate package (more info)

npm install grapnel-server

Declaring Multiple Routes

let routes = {
    'products' : function(req) {
        // GET /file.html#products
    },
    'products/:category/:id?' : function(req) {
        // GET /file.html#products/widgets/35
        console.log(req.params.category);
        // => widgets
    }
}

Grapnel.listen(routes);

Event Handling

const router = new Grapnel({ pushState : true, root : '/' });

router.on('navigate', function(event){
    // GET /foo/bar
    console.log('URL changed to %s', this.path());
    // => URL changed to /foo/bar
});

RegExp Support

Grapnel allows RegEx when defining a route:

const router = new Grapnel();
let expression = /^food\/tacos\/(.*)$/i;

router.get(expression, function(req, event){
    // GET http://mysite.com/page#food/tacos/good
    console.log('I think tacos are %s.', req.params[0]);
    // => "He thinks tacos are good."
});

Usage & Tips

Basic Configuration

const router = new Grapnel();

Enabling PushState

const router = new Grapnel({ pushState : true });

You can also specify a root URL by setting it as an option:

const router = new Grapnel({ root : '/app', pushState : true });

The root may require a beginning slash and a trailing slash depending on how you set up your routes.

Middleware

Grapnel uses middleware similar to how Express uses middleware. Middleware has access to the req object, route object, and the next middleware in the call stack (commonly denoted as next). Middleware must call next() to pass control to the next middleware, otherwise the router will stop.

For more information about how middleware works, see Using Middleware.

let user = function(req, route, next) {
    user.get(function(err) {
        req.user = this;
        next();
    });
}

router.get('/user/*', user, function(req) {
    console.log(req.user);
});

Declaring your routes with an object literal:

Grapnel.listen({
    'products/:id' : function(req) {
        // Handler
    }
});

When declaring routes with a literal object, router options can be passed as the first parameter:

let opts = { pushState : true };

Grapnel.listen(opts, routes);

Navigation

If pushState is enabled, you can navigate through your application with router.navigate:

router.navigate('/products/123');

Stopping a Route Event

router.on('match', function(routeEvent) {
    routeEvent.preventDefault(); // Stops event handler
});

Stopping Event Propagation

router.get('/products/:id', function(req, routeEvent) {
    routeEvent.stopPropagation(); // Stops propagation of the event
});

router.get('/products/widgets', function(req, routeEvent) {
    // This will not be executed
});

router.navigate('/products/widgets');

404 Pages

You can specify a route that only uses a wildcard * as your final route, then use route.parent() which returns false if the call stack doesn't have any other routes to run.

let routes = {
    '/' : function(req, route) {
        // Handle route
    },
    '/store/products/:id' : function(req, route) {
        // Handle route
    },
    '/category/:id' : function(req, route) {
        // Handle route
    },
    '/*' : function(req, route) {
        if(!route.parent()){
            // Handle 404
        }
    }
}

Grapnel.listen({ pushState : true }, routes);

Setting window state

router.navigate('/', {
    state: { ...windowState }
});

Documentation

get Adds a listeners and middleware for routes

/**
 * @param {String|RegExp} path
 * @param {Function} [[middleware], callback]
*/
router.get('/store/:category/:id?', function(req, route){
    let category = req.params.category;
    let id = req.params.id;

    console.log('Product #%s in %s', id, category);
});

navigate Navigate through application

/**
 * @param {String} path relative to root
 * @param {Object} options navigation options
*/
router.navigate('/products/123', ...options);

on Adds a new event listener

/**
 * @param {String} event name (multiple events can be called when separated by a space " ")
 * @param {Function} callback
*/
router.on('myevent', function(event) {
    console.log('Grapnel works!');
});

once A version of on except its handler will only be called once

/**
 * @param {String} event name (multiple events can be called when separated by a space " ")
 * @param {Function} callback
*/
router.once('init', function() {
    console.log('This will only be executed once');
});

emit Triggers an event

/**
 * @param {String} event name
 * @param {...Mixed} attributes Parameters that will be applied to event handler
*/
router.emit('event', eventArg1, eventArg2, ...etc);

context Returns a function that can be called with a specific route in context.

Both the router.context method and the function it returns can accept middleware. Note: when calling route.context, you should omit the trailing slash.

/**
 * @param {String} Route context (without trailing slash)
 * @param {[Function]} Middleware (optional)
 * @return {Function} Adds route to context
*/
let usersRoute = router.context('/user/:id');

usersRoute('/followers', function(req, route) {
    console.log('Followers', req.params.id);
});

router.navigate('/user/13589/followers');
// => Followers 13589

path

• router.path('string') Sets a new path or hash
• router.path() Gets path or hash
• router.path(false) Clears the path or hash

bind An alias of on

trigger An alias of emit

add An alias of get

Options

• pushState Enable pushState, allowing manipulation of browser history instead of using the # and hashchange event
• root Root of your app, all navigation will be relative to this
• target Target object where the router will apply its changes (default: window)
• hashBang Enable #! as the anchor of a hashchange router instead of using just a #

Events

• navigate Fires when router navigates through history
• match Fires when a new match is found, but before the handler is called
• hashchange Fires when hashtag is changed

License

MIT License