Grapnel

Simple, lightweight JavaScript Router with hash-based event handling

Website:https://github.com/gregsabia/Grapnel.js

Grapnel

The smallest (1100 bytes gzipped!) Client/Server-Side JavaScript Router with Named Parameters, HTML5 pushState, and Middleware support.

Download/Installation

Download Source:

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 Sinatra, Restify, and Express
  • Middleware Support
  • Works on the client or server-side
  • RegExp Support
  • RequreJS/AMD, Browserify, and CommonJS Compatibility
  • Supports # or #! for hashchange routing
  • Unobtrusive, supports multiple routers on the same page
  • No dependencies

Basic Router

var router = new Grapnel();

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

Using pushState

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

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

var 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:

var 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

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

npm install grapnel-server
var http = require('http'),
    app = require('grapnel-server');

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

http.createServer(app.start()).listen(3000);

Declaring Multiple Routes

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

Grapnel.listen(routes);

Event Handling

var 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:

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

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."
});

RequireJS/AMD, Browserify, and CommonJS Compatibility

require(['lib/grapnel'], function(Grapnel){

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

    router.bind('navigate', function(){
        console.log('It works!');
    });

    router.navigate('/');

});

 


Usage & Tips

Basic Configuration

var router = new Grapnel();

Or you can declare your routes with a literal object:

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

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

var opts = { pushState : true };

Grapnel.listen(opts, routes);

Enabling PushState

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

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

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

The root may require a beginning slash and a trailing slash depending on how your application utilizes the router.

Middleware

Grapnel uses middleware similar to how Express uses middleware. Middleware has access to the req object, event 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.

var user = function(req, event, next){
    user.get(function(err){
        req.user = this;
        next();
    });
}

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

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(event){
    event.preventDefault(); // Stops event handler
});

Stopping Event Propagation

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

router.get('/products/widgets', function(req, event){
    // 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 event.parent() which returns false if the call stack doesn't have any other routes to run.

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

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

 


API Documentation

get Adds a listeners and middleware for routes
/**
 * @param {String|RegExp} path
 * @param {Function} [[middleware], callback]
*/
router.get('/store/:category/:id?', function(req, event){
    var category = req.params.category,
        id = req.params.id;

    console.log('Product #%s in %s', id, category);
});
navigate Navigate through application
/**
 * @param {String} path relative to root
*/
router.navigate('/products/123');
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');
});
trigger Triggers an event
/**
 * @param {String} event name
 * @param {Mixed} [attributes] Parameters that will be applied to event handler
*/
router.trigger('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
*/
var usersRoute = router.context('/user/:id');

usersRoute('/followers', function(req, event){
    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
add An alias of get
fragment (Deprecated)

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
  • 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