JsRoutes

Generates javascript file that defines all Rails named routes as javascript helpers:

import { root_path, api_user_path } from './routes';

root_path() # => /
api_user_path(25, include_profile: true, format: 'json') // => /api/users/25.json?include_profile=true

More Examples

Intallation

Your Rails Gemfile:

gem "js-routes"

Setup

There are several possible ways to setup JsRoutes:

1. Quick and easy - Recommended

• Uses Rack Middleware to automatically update routes locally
• Automatically generates routes files on javascript build
• Works great for a simple Rails application

2. Advanced Setup

• Allows very custom setups
• Automatic updates need to be customized

3. Webpacker ERB Loader - Legacy

• Requires ESM module system (the default)
• Doesn't support typescript definitions

4. Sprockets - Legacy

• Deprecated and not recommended for modern apps

Quick Start

Setup Rack Middleware to automatically generate and maintain routes.js file and corresponding Typescript definitions routes.d.ts:

Use a Generator

Run a command:

rails generate js_routes:middleware

Setup Manually

Add the following to config/environments/development.rb:

  config.middleware.use(JsRoutes::Middleware)

Use it in any JS file:

import {post_path} from '../routes';

alert(post_path(1))

Upgrade js building process to update js-routes files in Rakefile:

task "javascript:build" => "js:routes"
# For setups without jsbundling-rails
task "assets:precompile" => "js:routes"

Add js-routes files to .gitignore:

/app/javascript/routes.js
/app/javascript/routes.d.ts

Webpacker ERB loader

IMPORTANT: the setup doesn't support IDE autocompletion with Typescript

Use a Generator

Run a command:

./bin/rails generate js_routes:webpacker

Setup manually

The routes files can be automatically updated without rake task being called manually. It requires rails-erb-loader npm package to work.

Add erb loader to webpacker:

yarn add rails-erb-loader
rm -f app/javascript/routes.js # delete static file if any

Create webpack ERB config config/webpack/loaders/erb.js:

module.exports = {
  module: {
    rules: [
      {
        test: /\.erb$/,
        enforce: 'pre',
        loader: 'rails-erb-loader'
      },
    ]
  }
};

Enable erb extension in config/webpack/environment.js:

const erb = require('./loaders/erb')
environment.loaders.append('erb', erb)

Create routes file app/javascript/routes.js.erb:

<%= JsRoutes.generate() %>

Use routes wherever you need them:

import {post_path} from 'routes.js.erb';

alert(post_path(2));

Advanced Setup

In case you need multiple route files for different parts of your application, there are low level methods:

# Returns a routes file as a string
JsRoutes.generate(options)
# Writes routes to specific file location
JsRoutes.generate!(file_name, options)
# Writes Typescript definitions file for routes
JsRoutes.definitions!(file_name, options)

They can also be used in ERB context

<script>
    var AdminRoutes = <%= JsRoutes.generate(
      include: /admin/, module_type: nil, namespace: nil
    ) %>;
</script>

Routes can be returns via API:

class Api::RoutesController < Api::BaseController
  def index
    options = {
      include: /\Aapi_/,
      default_url_options: { format: 'json' },
    }
    render json: {
      routes: {
        source: JsRoutes.generate(options),
        definitions: JsRoutes.definitions(options),
      }
    }
  end
end

Default auto-update middleware for development doesn't support configuration out of the box, but it can be extended through inheritence:

class AdvancedJsRoutesMiddleware < JsRoutes::Middleware
  def regenerate
    path = Rails.root.join("app/javascript")

    JsRoutes.generate!(
      "#{path}/app_routes.js", exclude: [/^admin_/, /^api_/]
    )
    JsRoutes.generate!(
    "#{path}/adm_routes.js", include: /^admin_/
    )
    JsRoutes.generate!(
      "#{path}/api_routes.js", include: /^api_/, default_url_options: {format: "json"}
    )
  end
end

Typescript Definitions

JsRoutes has typescript support out of the box.

Restrictions:

• Only available if module_type is set to ESM (strongly recommended and default).
• Webpacker Automatic Updates are not available because typescript compiler can not be configured to understand .erb extensions.

For the basic setup of typscript definitions see Quick Start setup. More advanced setup would involve calling manually:

JsRoutes.definitions! # to output to file
# or
JsRoutes.definitions # to output to string

Even more advanced setups can be achieved by setting module_type to DTS inside configuration which will cause any JsRoutes instance to generate defintions instead of routes themselves.

Sprockets (Deprecated)

If you are using Sprockets you may configure js-routes in the following way.

Setup the initializer (e.g. config/initializers/js_routes.rb):

JsRoutes.setup do |config|
  config.module_type = nil
  config.namespace = 'Routes'
end

Require JsRoutes in app/assets/javascripts/application.js or other bundle

//= require js-routes

Also in order to flush asset pipeline cache sometimes you might need to run:

rake tmp:cache:clear

This cache is not flushed on server restart in development environment.

Important: If routes.js file is not updated after some configuration change you need to run this rake task again.

Configuration

You can configure JsRoutes in two main ways. Either with an initializer (e.g. config/initializers/js_routes.rb):

JsRoutes.setup do |config|
  config.option = value
end

Or dynamically in JavaScript, although only Formatter Options are supported:

import {configure, config} from 'routes'

configure({
  option: value
});
config(); // current config

Available Options

Generator Options

Options to configure JavaScript file generator. These options are only available in Ruby context but not JavaScript.

• module_type - JavaScript module type for generated code. Article
  • Options: ESM, UMD, CJS, AMD, DTS, nil.
  • Default: ESM
  • nil option can be used in case you don't want generated code to export anything.
• documentation - specifies if each route should be annotated with JSDoc comment
  • Default: true
• exclude - Array of regexps to exclude from routes.
  • Default: []
  • The regexp applies only to the name before the _path suffix, eg: you want to match exactly settings_path, the regexp should be /^settings$/
• include - Array of regexps to include in routes.
  • Default: []
  • The regexp applies only to the name before the _path suffix, eg: you want to match exactly settings_path, the regexp should be /^settings$/
• namespace - global object used to access routes.
  • Only available if module_type option is set to nil.
  • Supports nested namespace like MyProject.routes
  • Default: nil
• camel_case - specifies if route helpers should be generated in camel case instead of underscore case.
  • Default: false
• url_links - specifies if *_url helpers should be generated (in addition to the default *_path helpers).
  • Default: false
  • Note: generated URLs will first use the protocol, host, and port options specified in the route definition. Otherwise, the URL will be based on the option specified in the default_url_options config. If no default option has been set, then the URL will fallback to the current URL based on window.location.
• compact - Remove _path suffix in path routes(*_url routes stay untouched if they were enabled)
  • Default: false
  • Sample route call when option is set to true: users() // => /users
• application - a key to specify which rails engine you want to generate routes too.
  • This option allows to only generate routes for a specific rails engine, that is mounted into routes instead of all Rails app routes
  • It is recommended to wrap the value with lambda. This will reduce the reliance on order during initialization your application.
  • Default: -> { Rails.application }
• file - a file location where generated routes are stored
  • Default: app/javascript/routes.js if setup with Webpacker, otherwise app/assets/javascripts/routes.js if setup with Sprockets.
• optional_definition_params - make all route paramters in definition optional
  • See related compatibility issue
  • Default: false
• banner - specify a JSDoc comment on top of the file.
  • It is not stripped by minifiers by default and helps to originate the content when debugging the build.
  • You may want to control how much information from backend is exposed to potential attacker at the cost of your own comfort.
  • See JSDoc Guide
  • Supports a lazy generation with Proc.
  • Default: A string that generates the following:

/**
 * File generated by js-routes 2.3.1 on 2024-12-04 09:45:59 +0100
 * Based on Rails 7.2.0 routes of App
 */

Formatter Options

Options to configure routes formatting. These options are available both in Ruby and JavaScript context.

• default_url_options - default parameters used when generating URLs
  • Example: {format: "json", trailing_slash: true, protocol: "https", subdomain: "api", host: "example.com", port: 3000}
  • See url_for doc for list of supported options
  • Default: {}
• serializer - a JS function that serializes a Javascript Hash object into URL paramters like {a: 1, b: 2} => "a=1&b=2".
  • Default: nil. Uses built-in serializer compatible with Rails
  • Example: jQuery.param - use jQuery's serializer algorithm. You can attach serialize function from your favorite AJAX framework.
  • Example: function (object) { ... } - use completely custom serializer of your application.
• special_options_key - a special key that helps JsRoutes to destinguish serialized model from options hash
  • This option exists because JS doesn't provide a difference between an object and a hash
  • Default: _options

Usage

Configuration above will create a nice javascript file with Routes object that has all the rails routes available:

import {
  user_path, user_project_path, company_path
} from 'routes';

users_path()
  // => "/users"

user_path(1)
  // => "/users/1"

user_path(1, {format: 'json'})
  // => "/users/1.json"

user_path(1, {anchor: 'profile'})
  // => "/users/1#profile"

new_user_project_path(1, {format: 'json'})
  // => "/users/1/projects/new.json"

user_project_path(1,2, {q: 'hello', custom: true})
  // => "/users/1/projects/2?q=hello&custom=true"

user_project_path(1,2, {hello: ['world', 'mars']})
  // => "/users/1/projects/2?hello%5B%5D=world&hello%5B%5D=mars"

var google = {id: 1, name: "Google"};
company_path(google)
  // => "/companies/1"

var google = {id: 1, name: "Google", to_param: "google"};
company_path(google)
  // => "/companies/google"

In order to make routes helpers available globally:

import * as Routes from '../routes';
jQuery.extend(window, Routes)

Get spec of routes and required params

Possible to get spec of route by function toString:

import {user_path, users_path}  from '../routes'

users_path.toString() // => "/users(.:format)"
user_path.toString() // => "/users/:id(.:format)"

Route function also contain method requiredParams inside which returns required param names array:

users_path.requiredParams() // => []
user_path.requiredParams() // => ['id']

Rails Compatibility

JsRoutes tries to replicate the Rails routing API as closely as possible. There are only 2 known issues with compatibility that happen very rarely and have their workarounds.

If you find any incompatibilities outside of ones below, please open an issue.

Object and Hash distinction issue

Sometimes the destinction between JS Hash and Object can not be found by JsRoutes. In this case you would need to pass a special key to help:

import {company_project_path} from '../routes'

company_project_path({company_id: 1, id: 2})
    // => Not enough parameters
company_project_path({company_id: 1, id: 2, _options: true})
    // => "/companies/1/projects/2"

Use special_options_key to configure the _options parameter name.

Rails required parameters specified as optional

Rails is very flexible on how route parameters can be specified. All of the following calls will make the same result:

# Given route
# /inboxes/:inbox_id/messages/:message_id/attachments/:id
# every call below returns:
# => "/inboxes/1/messages/2/attachments/3"

inbox_message_attachment_path(1, 2, 3)
inbox_message_attachment_path(1, 2, id: 3)
inbox_message_attachment_path(1, message_id: 2, id: 3)
inbox_message_attachment_path(inbox_id: 1, message_id: 2, id: 3)

# including these mad versions
inbox_message_attachment_path(2, inbox_id: 1, id: 3)
inbox_message_attachment_path(1, 3, message_id: 2)
inbox_message_attachment_path(3, inbox_id: 1, message_id: 2)

While all of these methods are supported by JsRoutes, it is impossible to support them in DTS type definitions. If you are using routes like this, use the following configuration that will prevent required parameters presence to be validated by definition:

JsRoutes.setup do |c|
  c.optional_definition_params = true
end

This will enforce the following route signature:

export const inbox_message_attachment_path: ((
  inbox_id?: RequiredRouteParameter,
  message_id?: RequiredRouteParameter,
  id?: RequiredRouteParameter,
  options?: RouteOptions
) => string) & RouteHelperExtras;

That will make every call above valid.

What about security?

JsRoutes itself does not have security holes. It makes URLs without access protection more reachable by potential attacker. If that is an issue for you, you may use one of the following solutions:

ESM Tree shaking

Make sure module_type is set to ESM (the default). Modern JS bundlers like Webpack can statically determine which ESM exports are used, and remove the unused exports to reduce bundle size. This is known as Tree Shaking.

JS files can use named imports to import only required routes into the file, like:

import {
  inbox_path,
  inboxes_path,
  inbox_message_path,
  inbox_attachment_path,
  user_path,
} from '../routes'

JS files can also use star imports (import * as) for tree shaking, as long as only explicit property accesses are used.

import * as routes from '../routes';

console.log(routes.inbox_path); // OK, only `inbox_path` is included in the bundle

console.log(Object.keys(routes)); // forces bundler to include all exports, breaking tree shaking

Exclude/Include options

Split your routes into multiple files related to each section of your website like:

JsRoutes.generate!('app/javascript/admin-routes.js', include: /^admin_/) %>
JsRoutes.generate!('app/javascript/app-routes.js', exclude: /^admin_/) %>

Advantages over alternatives

There are some alternatives available. Most of them has only basic feature and don't reach the level of quality I accept. Advantages of this one are:

• Actively maintained
• ESM Tree shaking support
• Rich options set
• Full rails compatibility
• Support Rails #to_param convention for seo optimized paths
• Well tested