automatically depend on all files listed in reference tags

Author: wtmcc

README.md

@@ -43,6 +43,9 @@ Configurations:
 Typescript::Rails::Compiler.default_options = [ ... ]
 ```
 
+## Referenced TypeScript dependencies
+
+`typescript-rails` recurses through all [TypeScript-style](https://github.com/teppeis/typescript-spec-md/blob/master/en/ch11.md#1111-source-files-dependencies) referenced files and tells its [`Sprockets::Context`](https://github.com/sstephenson/sprockets/blob/master/lib/sprockets/context.rb) that the TS file being processed [`depend`s`_on`](https://github.com/sstephenson/sprockets#the-depend_on-directive) each file listed as a reference. This activates Sprocket’s cache-invalidation behavior when any of the descendant references of the root TS file is changed.
 
 ## Contributing
 

lib/typescript/rails/compiler.rb

@@ -28,10 +28,36 @@ def replace_relative_references(ts_path, source)
       output
     end
 
+    # Get all references
+    #
+    # @param [String] path Source .ts path
+    # @param [String] source. It might be pre-processed by erb.
+    # @yieldreturn [String] matched ref abs_path
+    def get_all_reference_paths(path, source, visited_paths=Set.new, &block)
+      visited_paths << path
+      source ||= File.read(path)
+      source.each_line do |l|
+        if l.starts_with?('///') && !(m = %r!^///\s*<reference\s+path=(?:"([^"]+)"|'([^']+)')\s*/>\s*!.match(l)).nil?
+          matched_path = m.captures.compact[0]
+          abs_matched_path = File.expand_path(matched_path, File.dirname(path))
+          unless visited_paths.include? abs_matched_path
+            block.call abs_matched_path
+            get_all_reference_paths(abs_matched_path, nil, visited_paths, &block)
+          end
+        end
+      end
+    end
+
     # @param [String] ts_path
     # @param [String] source TypeScript source code
+    # @param [Sprockets::Context] sprockets context object
     # @return [String] compiled JavaScript source code
-    def compile(ts_path, source, *options)
+    def compile(ts_path, source, context=nil, *options)
+      if context
+        get_all_reference_paths(File.expand_path(ts_path), source) do |abs_path|
+          context.depend_on abs_path
+        end
+      end
       s = replace_relative_references(ts_path, source)
       ::TypeScript::Node.compile(s, *default_options, *options)
     end

lib/typescript/rails/template.rb

@@ -21,8 +21,8 @@ def prepare
     end
   end
 
-  def evaluate(scope, locals, &block)
-    @output ||= ::Typescript::Rails::Compiler.compile(file, data)
+  def evaluate(context, locals, &block)
+    @output ||= ::Typescript::Rails::Compiler.compile(file, data, context)
   end
 
   # @override

test/assets_test.rb

@@ -42,6 +42,7 @@ def assets
 
   test "assets .js.ts is compiled from TypeScript to JavaScript" do
     assert { assets["javascripts/hello"].present? }
+    assert { assets["javascripts/hello"].send(:dependency_paths).map(&:pathname).map(&:to_s).include? File.expand_path("#{File.dirname(__FILE__)}/fixtures/assets/javascripts/included.ts") }
     assert { assets["javascripts/hello"].body.include?('var s = "Hello, world!";') }
   end
 end

test/fixtures/assets/javascripts/hello.js.ts

@@ -1,2 +1,3 @@
+/// <reference path="reference.ts" />
 var s: string = "Hello, world!";
-console.log(s)
+log_to_console(s);

test/fixtures/assets/javascripts/included.ts

@@ -0,0 +1,4 @@
+/// <reference path="reference.ts" />
+var log_to_console = function(x: string): void {
+  console.log(x)
+}

test/fixtures/assets/javascripts/reference.ts

@@ -0,0 +1,2 @@
+/// <reference path="hello.js.ts" />
+/// <reference path="included.ts" />