A custom attribute for routing

m.attr.route.js

function route( node, route, attrs ){
	if( route instanceof String )
		route = [ route, {} ]
	
	var uri    = route[ 0 ]
	var params = route[ 1 ]
	var config = attrs.config
	
	for ( var key in params )
		if ( params.hasOwnProperty( key ){
			var placeholder = ':' + key
			var delimiter   = uri.indexOf( '?' ) > -1 )
				? '&'
				: '?'
		
			if( uri.indexOf( placeholder ) > -1 ){
				uri = uri.replace(
					placeholder,
					params[ key ]
				)
			}
			else {
				uri += delimiter + params[ key ]
			}
		}
	
	uri = uri.replace( /:([^\/:?&#]+)/g, function( match, param ){
		return m.route.param( param )
	} )

	node.href   = uri
	node.config = config
		? function(){
			config.apply( this, arguments )
			
			m.route.apply( this, arguments )
		}
		: m.route
}

Simple usage:

m( 'a', {
    route : '/location'
} )
// Instead of 
m( 'a', {
    href   : '/location',
    config : m.route
} )

For more complex needs:

m( 'a', {
    route : [ '/:user/:project', {
        user    : 'barney',
        project : 'mattr',
        page    : 2
    } ]
} )
// The resulting URI will be:
'/barney/mattr?page=2'

• Todo: fill in unspecified placeholders from the current route