js-rails-routes is a utility for generating javascript equivalents to the <route>_path functions provided by Ruby on Rails. This allows you to do very similar things in your ejs javascript templates as you would in your erb ruby templates. You can move html rendering to the client and keep it looking very similar to how it would look on the server.

For example, if you have a model Item and a simple route to list all the items, a link to that items page (using an explicit a anchor tag instead of the Rails link_to) would look the same in either an erb file or an ejs file:

<a href="<%= items_path() %>">List all Items</a>


To use js-rails-routes, first install it:

[sudo] gem install js-rails-routes

Command Line

Most likely you will want to run it on the command line, like so:


which will dump the generated javascript to stdout. Or, if you are in the base directory of a Ruby on Rails project that already has a directory app/assets/javascripts defined, you can run:

js-rails-routes --output

This will produce (clobber) the file app/assets/javascripts/routes.js.

You will then want to make sure the asset pipeline picks up the routes file. Inside your application.js:

//= require routes

Be default, the generated javascript will also contain a fairly simple implementation of the function link_to. If you do not wish to have this function added to the global namespace, you can suppress it with the command line flag --no-link-to.

Inside of Ruby

You can use it inside of a Ruby program by passing a String to the initializer of the JsRailsRoutes::Routes object and calling create_javascript:

require 'js-rails-routes'

result =

Using the Resulting JavaScript

In all the examples below, I assume using the client-side framework MVCoffee. It provides client-side models that closely mirror Rails models. The examples will assume the existence of these client models.

Simple Routes with no Parameters

The simplest case is a route that does not depend on a parameter. Suppose we have this simple route:

items              /items

In your javascript ejs template, you can do this:

<%= link_to("Show all items", items_path() ) %>

Route with one Parameter

Frequently a route depends on the id of a model, either to display that one entity or to edit it. For example, given this route:

edit_item          /item/:id/edit

You can either supply an integer as an argument for the id:

<%= link_to("Edit item number 42", edit_item_path(42) ) %>

Or you can provide a hash-like object literal, calling the parameter by name:

<%= link_to("Edit item number 42", edit_item_path( { id: 42 } ) ) %>

Since MVCoffee models are themselves hash-like objects, if you have a variable item holding the model entity with id = 42, you can do this:

<%= link_to("Edit item number 42", edit_item_path( item ) ) %>

Route with two or more Parameters

If you have more than one parameter in a route, you can either supply the parameters in the order in which they appear in the route, or as a named hash-like object literal. For example, given this route:

catalog_item      /catalog/:catalog_id/items/:id(.:format)

For catalog number 1, item number 2, you can do this:

<%= link_to("Cat 1, item 2", catalog_item_path(1, 2) ) %>

Or this:

<%= link_to("Cat 1, item 2", catalog_item_path( { catalog_id: 1, id: 2 } ) ) %>

Or this (assuming the variable item is a model with both fields id and catalog_id set):

<%= link_to("Cat 1, item 2", catalog_item_path( item ) ) %>


js-rails-routes depends on Ruby on Rails.

It also depends on by hoe and shoulda for development and testing.

Since hoe uses a README.txt file in rdoc format when publishing a gem, and github displays a file in markdown format, this gem uses rdoc2md to autogenerate the markdown file from the rdoc file. README.txt is the master. Do not edit by hand! In order to generate the markdown file, run rake


After checking out the source, run:

rake newb

This task will install any missing dependencies, run the tests/specs, and generate the RDoc.

This first pass is very ad-hoc. I make no claims that it exhaustively covers all possible Rails route formats. If you find a shortcoming, by all means, feel free to upgrade it. I welcome all contributions.

I do prefer that such shortcomings be documented first in the Issues. I may be working on a fix already. No sense in two people fixing the same thing….

I use the Git Flow development methodology. If you’d like to contribute, you should fork the develop branch and create a ‘feature’ subbranch.


js-rails-routes is released under the MIT license.