Add random dom id option (#1121)

* Added configuration option random_dom_id
* Added method RenderOptions has_random_dom_id?
This new global and react_component helper option allows configuring
whether or not React on Rails will automatically add a random id to the
DOM node ID.

docs/api/view-helpers-api.md

@@ -3,6 +3,8 @@
 
 Once the bundled files have been generated in your `app/assets/webpack` folder and you have registered your components, you will want to render these components on your Rails views using the included helper method, `react_component`.
 
+------------
+
 ### react_component
 
 ```ruby
@@ -24,11 +26,13 @@ react_component(component_name,
   - **id:** Id for the div, will be used to attach the React component. This will get assigned automatically if you do not provide an id. Must be unique.
   - **html_options:** Any other HTML options get placed on the added div for the component. For example, you can set a class (or inline style) on the outer div so that it behaves like a span, with the styling of `display:inline-block`.
   - **trace:** set to true to print additional debugging information in the browser. Defaults to true for development, off otherwise. Only on the **client side** will you will see the `railsContext` and your props.
+  - **random_dom_id:** True to automatically generate random dom ids when using multiple instances of the same React component on one Rails view.
 - **options if prerender (server rendering) is true:**
   - **replay_console:** Default is true. False will disable echoing server-rendering logs to the browser. While this can make troubleshooting server rendering difficult, so long as you have the configuration of `logging_on_server` set to true, you'll still see the errors on the server.
   - **logging_on_server:** Default is true. True will log JS console messages and errors to the server.
   - **raise_on_prerender_error:** Default is false. True will throw an error on the server side rendering. Your controller will have to handle the error.
 
+-------------
 
 ### react_component_hash
 
@@ -68,6 +72,8 @@ export default (props, _railsContext) => {
 
 ```
 
+------------
+
 ### cached_react_component and cached_react_component_hash
 Fragment caching is a [React on Rails Pro](https://github.com/shakacode/react_on_rails/wiki) feature. The API is the same as the above, but for 2 differences:
 
@@ -79,10 +85,13 @@ Fragment caching is a [React on Rails Pro](https://github.com/shakacode/react_on
   some_slow_method_that_returns_props
 end %>
 ```
+------------
+
 ### rails_context
 
 You can call `rails_context(server_side: true | false)` from your controller or view to see what values are are in the Rails Context. Pass true or false depending on whether you want to see the server side or the client side rails_context.
 
+------------
 
 ### Renderer Functions (function that will call ReactDOM.render or ReactDOM.hydrate)
 
@@ -92,6 +101,8 @@ Why would you want to call `ReactDOM.hydrate` yourself? One possible use case is
 
 Renderer functions are not meant to be used on the server since there's no DOM on the server. Instead, use a generator function. Attempting to server render with a renderer function will throw an error.
 
+------------
+
 ### React Router
 
 [React Router](https://github.com/reactjs/react-router) is supported, including server-side rendering! See:
@@ -100,6 +111,8 @@ Renderer functions are not meant to be used on the server since there's no DOM o
 2. Examples in [spec/dummy/app/views/react_router](../../spec/dummy/app/views/react_router) and follow to the JavaScript code in the [spec/dummy/client/app/startup/ServerRouterApp.jsx](../../spec/dummy/client/app/startup/ServerRouterApp.jsx).
 3. [Code Splitting docs](../misc-pending/code-splitting.md) for information about how to set up code splitting for server rendered routes.
 
+------------
+
 ## server_render_js
 
 `server_render_js(js_expression, options = {})`
@@ -109,6 +122,8 @@ Renderer functions are not meant to be used on the server since there's no DOM o
 
 This is a helper method that takes any JavaScript expression and returns the output from evaluating it. If you have more than one line that needs to be executed, wrap it in an IIFE. JS exceptions will be caught and console messages handled properly.
 
+------------
+
 # More details
 
 See the [lib/react_on_rails/helper.rb](../../lib/react_on_rails/helper.rb) source.

docs/basics/configuration.md

@@ -12,6 +12,15 @@ ReactOnRails.configure do |config|
   # setInterval, clearTimout when server rendering.
   config.trace = Rails.env.development?
 
+  # Configure if default DOM IDs have a random value or are fixed.
+  # false ==> Sets the dom id to "#{react_component_name}-react-component"
+  # true ==> Adds "-#{SecureRandom.uuid}" to that ID
+  # If you might use multiple instances of the same React component on a Rails page, then
+  # it is convenient to set this to true or else you have to either manually set the ids to 
+  # avoid collisions. Most newer apps will have only one instance of a component on a page,
+  # so this should be false in most cases.
+  # This value can be overrident for a given call to react_component
+  config.random_dom_id = false # default is true
 
   # defaults to "" (top level)
   #

lib/react_on_rails/configuration.rb

@@ -9,6 +9,7 @@ def self.configure
   DEFAULT_GENERATED_ASSETS_DIR = File.join(%w[public webpack], Rails.env).freeze
   DEFAULT_SERVER_RENDER_TIMEOUT = 20
   DEFAULT_POOL_SIZE = 1
+  DEFAULT_RANDOM_DOM_ID = TRUE # for backwards compatability
 
   def self.configuration
     @configuration ||= Configuration.new(
@@ -32,7 +33,8 @@ def self.configuration
       server_render_method: nil,
       symlink_non_digested_assets_regex: nil,
       build_test_command: "",
-      build_production_command: ""
+      build_production_command: "",
+      random_dom_id: DEFAULT_RANDOM_DOM_ID
     )
   end
 
@@ -45,7 +47,7 @@ class Configuration
                   :webpack_generated_files, :rendering_extension, :build_test_command,
                   :build_production_command,
                   :i18n_dir, :i18n_yml_dir,
-                  :server_render_method, :symlink_non_digested_assets_regex
+                  :server_render_method, :symlink_non_digested_assets_regex, :random_dom_id
 
     def initialize(node_modules_location: nil, server_bundle_js_file: nil, prerender: nil,
                    replay_console: nil,
@@ -56,7 +58,7 @@ def initialize(node_modules_location: nil, server_bundle_js_file: nil, prerender
                    generated_assets_dir: nil, webpack_generated_files: nil,
                    rendering_extension: nil, build_test_command: nil,
                    build_production_command: nil,
-                   i18n_dir: nil, i18n_yml_dir: nil,
+                   i18n_dir: nil, i18n_yml_dir: nil, random_dom_id: nil,
                    server_render_method: nil, symlink_non_digested_assets_regex: nil)
       self.node_modules_location = node_modules_location.present? ? node_modules_location : Rails.root
       self.server_bundle_js_file = server_bundle_js_file
@@ -67,6 +69,7 @@ def initialize(node_modules_location: nil, server_bundle_js_file: nil, prerender
       self.i18n_dir = i18n_dir
       self.i18n_yml_dir = i18n_yml_dir
 
+      self.random_dom_id = random_dom_id
       self.prerender = prerender
       self.replay_console = replay_console
       self.logging_on_server = logging_on_server

lib/react_on_rails/helper.rb

@@ -98,6 +98,7 @@ def env_stylesheet_link_tag(args = {})
     #   raise_on_prerender_error: <true/false> Default to false. True will raise exception on server
     #      if the JS code throws
     # Any other options are passed to the content tag, including the id.
+    # random_dom_id can be set to override the global default.
     def react_component(component_name, options = {})
       internal_result = internal_react_component(component_name, options)
       server_rendered_html = internal_result[:result]["html"]

lib/react_on_rails/react_component/render_options.rb

@@ -22,8 +22,26 @@ def props
         options.fetch(:props) { NO_PROPS }
       end
 
+      def random_dom_id
+        retrieve_key(:random_dom_id)
+      end
+
       def dom_id
-        @dom_id ||= options.fetch(:id) { generate_unique_dom_id }
+        @dom_id ||= options.fetch(:id) do
+          if random_dom_id
+            generate_unique_dom_id
+          else
+            base_dom_id
+          end
+        end
+      end
+
+      def has_random_dom_id?
+        return false if options[:id]
+
+        return false unless random_dom_id
+
+        true
       end
 
       def html_options
@@ -58,8 +76,12 @@ def to_s
 
       attr_reader :options
 
+      def base_dom_id
+       "#{react_component_name}-react-component"
+      end
+
       def generate_unique_dom_id
-        "#{react_component_name}-react-component-#{SecureRandom.uuid}"
+        "#{base_dom_id}-#{SecureRandom.uuid}"
       end
 
       def retrieve_key(key)

spec/dummy/Gemfile.lock

@@ -7,7 +7,7 @@ GIT
 PATH
   remote: ../..
   specs:
-    react_on_rails (11.0.9)
+    react_on_rails (11.0.10)
       addressable
       connection_pool
       execjs (~> 2.5)
@@ -352,4 +352,4 @@ DEPENDENCIES
   webpacker
 
 BUNDLED WITH
-   1.16.2
+   1.16.3

spec/dummy/config/initializers/react_on_rails.rb

@@ -16,6 +16,7 @@ def self.custom_context(view_context)
 end
 
 ReactOnRails.configure do |config|
+  config.random_dom_id = false # default is true
   config.node_modules_location = "client" # Pre 9.0.0 always used "client"
   config.build_production_command = "yarn run build:production"
   config.build_test_command = "yarn run build:test"

spec/dummy/spec/helpers/react_on_rails_helper_spec.rb

@@ -87,23 +87,34 @@
       { name: "My Test Name" }
     end
 
-    let(:react_component_div) do
+    let(:react_component_random_id_div) do
       '<div id="App-react-component-0"></div>'
     end
 
+    let(:react_component_div) do
+      '<div id="App-react-component"></div>'
+    end
+
     let(:id) { "App-react-component-0" }
 
-    let(:react_definition_script) do
+    let(:react_definition_script_random) do
       <<-SCRIPT.strip_heredoc
         <script type="application/json" class="js-react-on-rails-component" \
         data-component-name="App" data-dom-id="App-react-component-0">{"name":"My Test Name"}</script>
       SCRIPT
     end
 
+    let(:react_definition_script) do
+      <<-SCRIPT.strip_heredoc
+        <script type="application/json" class="js-react-on-rails-component" \
+        data-component-name="App" data-dom-id="App-react-component">{"name":"My Test Name"}</script>
+      SCRIPT
+    end
+
     let(:react_definition_script_no_params) do
       <<-SCRIPT.strip_heredoc
         <script type="application/json" class="js-react-on-rails-component" \
-        data-component-name="App" data-dom-id="App-react-component-0">{}</script>
+        data-component-name="App" data-dom-id="App-react-component">{}</script>
       SCRIPT
     end
 
@@ -121,7 +132,7 @@
       it { is_expected.to include json_props_sanitized }
     end
 
-    describe "API with component name only" do
+    describe "API with component name only (no props or other options)" do
       subject { react_component("App") }
       it { is_expected.to be_an_instance_of ActiveSupport::SafeBuffer }
       it { is_expected.to include react_component_div }
@@ -140,6 +151,51 @@
       expect(is_expected.target).to script_tag_be_included(react_definition_script)
     }
 
+    context "with 'random_dom_id' false option" do
+      subject { react_component("App", props: props, random_dom_id: false) }
+
+      let(:react_definition_script) do
+        <<-SCRIPT.strip_heredoc
+          <script type="application/json" class="js-react-on-rails-component" data-component-name="App" data-dom-id="App-react-component">{"name":"My Test Name"}</script>
+        SCRIPT
+      end
+
+      it { is_expected.to include '<div id="App-react-component"></div>' }
+      it { expect(is_expected.target).to script_tag_be_included(react_definition_script) }
+    end
+
+    context "with 'random_dom_id' false option" do
+      subject { react_component("App", props: props, random_dom_id: true) }
+
+      let(:react_definition_script) do
+        <<-SCRIPT.strip_heredoc
+          <script type="application/json" class="js-react-on-rails-component" data-component-name="App" data-dom-id="App-react-component-0">{"name":"My Test Name"}</script>
+        SCRIPT
+      end
+
+      it { is_expected.to include '<div id="App-react-component-0"></div>' }
+      it { expect(is_expected.target).to script_tag_be_included(react_definition_script) }
+    end
+
+    context "with 'random_dom_id' global" do
+      around(:example) do |example|
+        ReactOnRails.configure { |config| config.random_dom_id = false }
+        example.run
+        ReactOnRails.configure { |config| config.random_dom_id = true }
+      end
+
+      subject { react_component("App", props: props) }
+
+      let(:react_definition_script) do
+        <<-SCRIPT.strip_heredoc
+          <script type="application/json" class="js-react-on-rails-component" data-component-name="App" data-dom-id="App-react-component">{"name":"My Test Name"}</script>
+        SCRIPT
+      end
+
+      it { is_expected.to include '<div id="App-react-component"></div>' }
+      it { expect(is_expected.target).to script_tag_be_included(react_definition_script) }
+    end
+
     context "with 'id' option" do
       subject { react_component("App", props: props, id: id) }
 
@@ -152,7 +208,7 @@
       end
 
       it { is_expected.to include id }
-      it { is_expected.not_to include react_component_div }
+      it { is_expected.not_to include react_component_random_id_div }
       it {
         expect(is_expected.target).to script_tag_be_included(react_definition_script)
       }
@@ -217,6 +273,8 @@
       ReactOnRails.configuration.rendering_extension = nil
     end
 
+    after { ReactOnRails.configuration.rendering_extension = @rendering_extension }
+
     it "should not throw an error if not in a view" do
       class PlainClass
         include ReactOnRailsHelper
@@ -226,7 +284,5 @@ class PlainClass
       expect { ob.send(:rails_context, server_side: true) }.to_not raise_error
       expect { ob.send(:rails_context, server_side: false) }.to_not raise_error
     end
-
-    after { ReactOnRails.configuration.rendering_extension = @rendering_extension }
   end
 end