Replace Sprockets with esbuild, convert JS to TypeScript

* Remove Sprockets, Uglifier, and sass gem dependencies
* esbuild compiles TypeScript directly and minifies in 2ms

Author: sferik

Gemfile

@@ -24,9 +24,6 @@ group :development do
   gem "rubocop-minitest"
   gem "rubocop-performance"
   gem "rubocop-rake"
-  gem "sass"
-  gem "sprockets"
-  gem "uglifier"
 end
 
 gem "logger" if RUBY_VERSION >= "3.4"

Gemfile.lock

@@ -1,6 +1,6 @@
 GIT
   remote: https://github.com/simplecov-ruby/simplecov
-  revision: 3d8d723874ff14b06f30dee5d1453f9acc92fdf9
+  revision: 7245d3a1292f4feb17c8876c5357e4034b0595a4
   specs:
     simplecov (0.22.0)
       docile (~> 1.1)
@@ -16,18 +16,14 @@ GEM
   remote: https://rubygems.org/
   specs:
     ast (2.4.3)
-    concurrent-ruby (1.3.6)
     docile (1.4.1)
     drb (2.2.3)
-    execjs (2.10.0)
-    ffi (1.17.4-arm64-darwin)
-    ffi (1.17.4-java)
     json (2.19.3)
     json (2.19.3-java)
     language_server-protocol (3.17.0.5)
     lint_roller (1.1.0)
     logger (1.7.0)
-    minitest (6.0.2)
+    minitest (6.0.3)
       drb (~> 2.0)
       prism (~> 1.5)
     nokogiri (1.19.2-arm64-darwin)
@@ -41,12 +37,8 @@ GEM
     prism (1.9.0)
     racc (1.8.1)
     racc (1.8.1-java)
-    rack (3.2.5)
     rainbow (3.1.1)
     rake (13.3.1)
-    rb-fsevent (0.11.2)
-    rb-inotify (0.11.1)
-      ffi (~> 1.0)
     regexp_parser (2.11.3)
     rubocop (1.86.0)
       json (~> 2.3)
@@ -74,18 +66,7 @@ GEM
       lint_roller (~> 1.1)
       rubocop (>= 1.72.1)
     ruby-progressbar (1.13.0)
-    sass (3.7.4)
-      sass-listen (~> 4.0.0)
-    sass-listen (4.0.0)
-      rb-fsevent (~> 0.9, >= 0.9.4)
-      rb-inotify (~> 0.9, >= 0.9.7)
     simplecov_json_formatter (0.1.4)
-    sprockets (4.2.2)
-      concurrent-ruby (~> 1.0)
-      logger
-      rack (>= 2.2.4, < 4)
-    uglifier (4.2.1)
-      execjs (>= 0.3.0, < 3)
     unicode-display_width (3.2.0)
       unicode-emoji (~> 4.1)
     unicode-emoji (4.2.0)
@@ -104,11 +85,8 @@ DEPENDENCIES
   rubocop-minitest
   rubocop-performance
   rubocop-rake
-  sass
   simplecov!
   simplecov-html!
-  sprockets
-  uglifier
 
 BUNDLED WITH
   4.0.9

Rakefile

@@ -30,26 +30,26 @@ end
 task default: %i[test rubocop]
 
 namespace :assets do
-  desc "Compiles all assets"
+  desc "Compiles all assets using esbuild"
   task :compile do
     puts "Compiling assets"
-    require "sprockets"
-    require "sprockets/sass_processor"
 
-    Sprockets.register_processor("text/css") do |input|
-      {data: input[:data].gsub(/(?<!-|_)url\(['"]?(.+?)['"]?\)/) { "asset-data-url(\"#{Regexp.last_match(1)}\")" }}
+    # JS: esbuild compiles TypeScript directly, then we concatenate with highlight.js and minify
+    sh "esbuild src/app.ts --bundle --minify --target=es2015 " \
+       "--banner:js=\"$(cat assets/javascripts/plugins/highlight.pack.js)\" " \
+       "--outfile=public/application.js"
+
+    # CSS: concatenate in order and minify
+    css = %w[
+      assets/stylesheets/reset.css
+      assets/stylesheets/plugins/highlight.css
+      assets/stylesheets/screen.css
+    ].map { |f| File.read(f) }.join("\n")
+
+    IO.popen(%w[esbuild --minify --loader=css], "r+") do |io|
+      io.write(css)
+      io.close_write
+      File.write("public/application.css", io.read)
     end
-
-    Sprockets.register_processor "text/css", Sprockets::ScssProcessor
-
-    assets = Sprockets::Environment.new do |env|
-      env.append_path "assets/javascripts"
-      env.append_path "assets/stylesheets"
-      env.append_path "public"
-      env.js_compressor = :uglify
-      env.css_compressor = :scss
-    end
-    assets["application.js"].write_to("public/application.js")
-    assets["application.css"].write_to("public/application.css")
   end
 end