Add static assets support

.rubocop.yml

@@ -0,0 +1,124 @@
+AllCops:
+  TargetRubyVersion: 2.2
+  # RuboCop has a bunch of cops enabled by default. This setting tells RuboCop
+  # to ignore them, so only the ones explicitly set in this file are enabled.
+  DisabledByDefault: true
+  Exclude:
+    - 'lib/install/templates/**'
+    - 'vendor/**/*'
+    - 'node_modules/**/*'
+
+# Prefer &&/|| over and/or.
+Style/AndOr:
+  Enabled: true
+
+# Do not use braces for hash literals when they are the last argument of a
+# method call.
+Style/BracesAroundHashParameters:
+  Enabled: true
+
+# Align `when` with `case`.
+Style/CaseIndentation:
+  Enabled: true
+
+# Align comments with method definitions.
+Style/CommentIndentation:
+  Enabled: true
+
+# No extra empty lines.
+Style/EmptyLines:
+  Enabled: true
+
+# In a regular class definition, no empty lines around the body.
+Style/EmptyLinesAroundClassBody:
+  Enabled: true
+
+# In a regular method definition, no empty lines around the body.
+Style/EmptyLinesAroundMethodBody:
+  Enabled: true
+
+# In a regular module definition, no empty lines around the body.
+Style/EmptyLinesAroundModuleBody:
+  Enabled: true
+
+# Use Ruby >= 1.9 syntax for hashes. Prefer { a: :b } over { :a => :b }.
+Style/HashSyntax:
+  Enabled: true
+
+# Method definitions after `private` or `protected` isolated calls need one
+# extra level of indentation.
+Style/IndentationConsistency:
+  Enabled: true
+  EnforcedStyle: rails
+
+# Two spaces, no tabs (for indentation).
+Style/IndentationWidth:
+  Enabled: true
+
+Style/SpaceAfterColon:
+  Enabled: true
+
+Style/SpaceAfterComma:
+  Enabled: true
+
+Style/SpaceAroundEqualsInParameterDefault:
+  Enabled: true
+
+Style/SpaceAroundKeyword:
+  Enabled: true
+
+Style/SpaceAroundOperators:
+  Enabled: true
+
+Style/SpaceBeforeFirstArg:
+    Enabled: true
+
+# Defining a method with parameters needs parentheses.
+Style/MethodDefParentheses:
+  Enabled: true
+
+# Use `foo {}` not `foo{}`.
+Style/SpaceBeforeBlockBraces:
+  Enabled: true
+
+# Use `foo { bar }` not `foo {bar}`.
+Style/SpaceInsideBlockBraces:
+  Enabled: true
+
+# Use `{ a: 1 }` not `{a:1}`.
+Style/SpaceInsideHashLiteralBraces:
+  Enabled: true
+
+Style/SpaceInsideParens:
+  Enabled: true
+
+# Check quotes usage according to lint rule below.
+Style/StringLiterals:
+  Enabled: true
+  EnforcedStyle: double_quotes
+
+# Detect hard tabs, no hard tabs.
+Style/Tab:
+  Enabled: true
+
+# Blank lines should not have any spaces.
+Style/TrailingBlankLines:
+  Enabled: true
+
+# No trailing whitespace.
+Style/TrailingWhitespace:
+  Enabled: true
+
+# Use quotes for string literals when they are enough.
+Style/UnneededPercentQ:
+  Enabled: true
+
+# Align `end` with the matching keyword or starting expression except for
+# assignments, where it should be aligned with the LHS.
+Lint/EndAlignment:
+  Enabled: true
+  EnforcedStyleAlignWith: variable
+
+# Use my_method(my_arg) not my_method( my_arg ) or my_method my_arg.
+Lint/RequireParentheses:
+  Enabled: true

.travis.yml

@@ -13,10 +13,12 @@ cache:
   yarn: true
 
 install:
+  - gem install rubocop
   - nvm install node
   - node -v
   - npm i -g yarn
   - yarn
 
 script:
   - yarn lint
+  - rubocop

Gemfile

@@ -1,3 +1,3 @@
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
 gemspec

README.md

@@ -15,14 +15,16 @@ Webpacker is currently compatible with Rails 4.2+, but there's no guarantee it w
 in the future.
 
 You can either make use of Webpacker during setup of a new application with `--webpack`
-or you can add the gem and run `bin/rails webpacker:install` in an existing application.
+or you can add the gem and run `./bin/rails webpacker:install` in an existing application.
 
 As the rubygems version isn't promised to be kept up to date until the release of Rails 5.1, you may want to include the gem directly from GitHub:
 
 ```ruby
 gem 'webpacker', github: 'rails/webpacker'
 ```
 
+You can also see a list of available commands by running `./bin/rails webpacker`
+
 ## Binstubs
 
 Webpacker ships with three binstubs: `./bin/webpack`, `./bin/webpack-watcher` and `./bin/webpack-dev-server`.
@@ -78,13 +80,62 @@ app/javascript/calendar/models/month.js
 But it could also look a million other ways. The only convention that Webpacker enforces is the
 one where entry points are automatically configured by the files in `app/javascript/packs`.
 
+## Advanced Configuration
+
+By default, webpacker provides simple conventions for where the webpack configs, javascript app files and compiled webpack bundles will go in your rails app, but all these are configurable from package.json that comes with webpacker. You can also configure webpack-dev-server host and port in your development environment
+
+```json
+{
+  "config": {
+    "_comment": "Configure webpacker internals (do not remove)",
+    "webpacker": {
+      "srcPath": "app/javascript",
+      "configPath": "config/webpack",
+      "nodeModulesPath": "node_modules",
+      "distDir": "packs",
+      "distPath": "public/packs",
+      "digestFileName": "digests.json"
+    },
+    "_comment": "Configure webpack-dev-server",
+    "devServer": {
+      "enabled": true,
+      "host": "localhost",
+      "port": "8080",
+      "compress": true
+    }
+  }
+}
+```
+
+**For ex:** if you rename `packs` directory inside `app/javascript` from `packs` to `bundles`, make sure you also update your `distDir` and `distPath`.
+
+```json
+"webpacker": {
+  "distDir": "bundles",
+  "distPath": "public/bundles",
+}
+```
+
+**Note:** Do not delete this config otherwise your app will break, unless you really know what you're doing.
 
 ## Deployment
 
-To compile all the packs during deployment, you can use the `rails webpacker:compile` command. This
-will invoke the production configuration, which includes digesting. The `javascript_pack_tag` helper
-method will automatically insert the correct digest when run in production mode. Just like the asset
-pipeline does it.
+Webpacker hooks up a new `webpacker:compile` task to `assets:precompile`, which gets run whenever you run `assets:precompile`. The `javascript_pack_tag` and `stylesheet_pack_tag` helper method will automatically insert the correct HTML tag for compiled pack. Just like the asset pipeline does it. By default the output will look like this in different environments,
+
+```html
+  <!-- In development mode with webpack-dev-server -->
+  <script src="http://localhost:8080/calendar.js"></script>
+  <link rel="stylesheet" media="screen" href="http://localhost:8080/calendar.css">
+  <!-- In development mode -->
+  <script src="/packs/calendar.js"></script>
+  <link rel="stylesheet" media="screen" href="/packs/calendar.css">
+  <!-- In production mode -->
+  <script src="/packs/calendar-0bd141f6d9360cf4a7f5.js"></script>
+  <link rel="stylesheet" media="screen" href="/packs/calendar-dc02976b5f94b507e3b6.css">
+```
+
+**Note:** *`stylesheet_pack_tag` helper is not available out-of-the-box.
+Check [statics assets](#ready-for-static-assets) support section for more details.*
 
 ## Linking to sprockets assets
 
@@ -100,27 +151,54 @@ var railsImagePath = "<%= helpers.image_path('rails.png') %>";
 
 This is enabled by the `rails-erb-loader` loader rule in `config/webpack/shared.js`.
 
+## Ready for Static Assets
+
+Static assets support isn't enabled out-of-the-box. To enable static assets support in your javascript app you will need to run `rails webpacker:install:assets` after you have installed webpacker. Once installed, you can
+link static files like images and styles directly into your javascript app code and
+have them properly compiled automatically.
+
+```js
+// React component example
+// app/javascripts/packs/hello_react.jsx
+import React from 'react'
+import ReactDOM from 'react-dom'
+import clockIcon from '../counter/images/clock.png'
+import './hello-react.sass'
+
+const Hello = props => (
+  <div className="hello-react">
+    <img src={clockIcon} alt="clock" />
+    <p>Hello {props.name}!</p>
+  </div>
+)
+```
+
+and then within your view, include the `stylesheet_pack_tag` with the name of your pack,
+
+```erb
+<%= stylesheet_pack_tag 'hello_react' %>
+```
+
 ## Ready for React
 
-To use Webpacker with React, just create a new app with `rails new myapp --webpack=react` (or run `rails webpacker:install:react` on a Rails 5.1 app already setup with webpack), and all the relevant dependencies
+To use Webpacker with React, just create a new app with `rails new myapp --webpack=react` (or run `rails webpacker:install:react` on a Rails app already setup with webpacker), and all the relevant dependencies
 will be added via yarn and changes to the configuration files made. Now you can create JSX files and
 have them properly compiled automatically.
 
 ## Ready for Angular with TypeScript
 
-To use Webpacker with Angular, just create a new app with `rails new myapp --webpack=angular` (or run `rails webpacker:install:angular` on a Rails 5.1 app already setup with webpack). TypeScript support and the Angular core libraries will be added via yarn and changes to the configuration files made. An example component written in TypeScript is also added to your project in `app/javascript` so that you can experiment Angular right away.
+To use Webpacker with Angular, just create a new app with `rails new myapp --webpack=angular` (or run `rails webpacker:install:angular` on a Rails app already setup with webpacker). TypeScript support and the Angular core libraries will be added via yarn and changes to the configuration files made. An example component written in TypeScript is also added to your project in `app/javascript` so that you can experiment Angular right away.
 
 ## Ready for Vue
 
-To use Webpacker with Vue, just create a new app with `rails new myapp --webpack=vue` (or run `rails webpacker:install:vue` on a Rails 5.1 app already setup with webpack). Vue and its supported libraries will be added via yarn and changes to the configuration files made. An example component is also added to your project in `app/javascript` so that you can experiment Vue right away.
+To use Webpacker with Vue, just create a new app with `rails new myapp --webpack=vue` (or run `rails webpacker:install:vue` on a Rails app already setup with webpacker). Vue and its supported libraries will be added via yarn and changes to the configuration files made. An example component is also added to your project in `app/javascript` so that you can experiment Vue right away.
 
 
 ## Wishlist
 
 - Improve process for linking to assets compiled by sprockets - shouldn't need to specify
 ` <% helpers = ActionController::Base.helpers %>` at the beginning of each file
 - Consider chunking setup
-- Consider on-demand compiling with digests when digesting=true
 
 ## License
 Webpacker is released under the [MIT License](https://opensource.org/licenses/MIT).

lib/install/bin/webpack-dev-server.tt

@@ -1,27 +1,40 @@
 <%= shebang %>
+$stdout.sync = true
+
 require 'shellwords'
+require 'json'
 
 ENV['RAILS_ENV'] ||= 'development'
-RAILS_ENV   = ENV['RAILS_ENV']
+RAILS_ENV = ENV['RAILS_ENV']
 
 ENV['NODE_ENV'] ||= RAILS_ENV
-NODE_ENV    = ENV['NODE_ENV']
+NODE_ENV = ENV['NODE_ENV']
 
 APP_PATH = File.expand_path('../', __dir__)
 ESCAPED_APP_PATH = APP_PATH.shellescape
 
-SET_NODE_PATH  = "NODE_PATH=#{ESCAPED_APP_PATH}/node_modules"
-WEBPACKER_BIN  = "./node_modules/.bin/webpack-dev-server"
-WEBPACK_CONFIG = "#{ESCAPED_APP_PATH}/config/webpack/#{NODE_ENV}.js"
+begin
+  package_json = File.read(File.join(APP_PATH, 'package.json'))
+  config = JSON.parse(package_json)
 
-# Warn the user if the configuration is not set
-RAILS_ENV_CONFIG = File.join("config", "environments", "#{RAILS_ENV}.rb")
+  NODE_MODULES_PATH = "#{File.join(ESCAPED_APP_PATH, config['webpacker']['nodeModulesPath'])}"
+  WEBPACK_CONFIG_PATH = "#{File.join(ESCAPED_APP_PATH, config['webpacker']['configPath'])}"
+  PACKS_PATH = "#{File.join(ESCAPED_APP_PATH, config['webpacker']['distPath'])}"
+  WEBPACK_BIN  = "#{NODE_MODULES_PATH}/.bin/webpack-dev-server"
+  WEBPACK_CONFIG = "#{WEBPACK_CONFIG_PATH}/development.hot.js"
 
-# Look into the environment file for a non-commented variable declaration
-unless File.foreach(File.join(APP_PATH, RAILS_ENV_CONFIG)).detect { |line| line.match(/^\s*[^#]*config\.x\.webpacker\[\:dev_server_host\].*=/) }
-  puts "Warning: if you want to use webpack-dev-server, you need to tell Webpacker to serve asset packs from it. Please set config.x.webpacker[:dev_server_host] in #{RAILS_ENV_CONFIG}.\n\n"
+  if config['devServer'] && !config['devServer']['enabled']
+    puts "Error: If you want to use webpack-dev-server, you will need to enable " \
+        "webpack-dev-server from your package.json { devServer: { enabled: true } }"
+    exit!
+  end
+rescue Errno::ENOENT, NoMethodError
+  puts 'Package.json or [webpacker, devServer] config key not found.'
+  puts 'Please run bundle exec rails webpacker:install to install webpacker'
+  exit!
 end
 
 Dir.chdir(APP_PATH) do
-  exec "#{SET_NODE_PATH} #{WEBPACKER_BIN} --config #{WEBPACK_CONFIG} --content-base #{ESCAPED_APP_PATH}/public/packs #{ARGV.join(" ")}"
+  exec "NODE_PATH=#{NODE_MODULES_PATH} #{WEBPACK_BIN} " \
+  "--config #{WEBPACK_CONFIG} --content-base #{PACKS_PATH} #{ARGV.join(" ")}"
 end

lib/install/bin/webpack.tt

@@ -1,5 +1,8 @@
 <%= shebang %>
+$stdout.sync = true
+
 require 'shellwords'
+require 'json'
 
 ENV['RAILS_ENV'] ||= 'development'
 RAILS_ENV   = ENV['RAILS_ENV']
@@ -10,10 +13,22 @@ NODE_ENV    = ENV['NODE_ENV']
 APP_PATH = File.expand_path('../', __dir__)
 ESCAPED_APP_PATH = APP_PATH.shellescape
 
-SET_NODE_PATH  = "NODE_PATH=#{ESCAPED_APP_PATH}/node_modules"
-WEBPACK_BIN    = "./node_modules/webpack/bin/webpack.js"
-WEBPACK_CONFIG = "#{ESCAPED_APP_PATH}/config/webpack/#{NODE_ENV}.js"
+begin
+  package_json = File.read(File.join(APP_PATH, 'package.json'))
+  config = JSON.parse(package_json)
+
+  NODE_MODULES_PATH = "#{File.join(ESCAPED_APP_PATH, config['webpacker']['nodeModulesPath'])}"
+  WEBPACK_CONFIG_PATH = "#{File.join(ESCAPED_APP_PATH, config['webpacker']['configPath'])}"
+rescue Errno::ENOENT, NoMethodError
+  puts 'Package.json or [webpacker, devServer] config key not found.'
+  puts 'Please run bundle exec rails webpacker:install to install webpacker'
+  exit!
+end
+
+WEBPACK_BIN  = "#{NODE_MODULES_PATH}/.bin/webpack"
+WEBPACK_CONFIG = "#{WEBPACK_CONFIG_PATH}/#{NODE_ENV}.js"
 
 Dir.chdir(APP_PATH) do
-  exec "#{SET_NODE_PATH} #{WEBPACK_BIN} --config #{WEBPACK_CONFIG} #{ARGV.join(" ")}"
+  exec "NODE_PATH=#{NODE_MODULES_PATH} #{WEBPACK_BIN} --config #{WEBPACK_CONFIG}" \
+  " #{ARGV.join(" ")}"
 end