Tailwindcss debug environment variable (#504)

* Add TAILWINDCSS_DEBUG environment variable

* Update README

* ENV var should take precedence over command argument

* prefer Hash.key? to !Hash[].nil?

---------

Co-authored-by: Mike Dalessio <mike@37signals.com>

Author: r-sierra

README.md

@@ -288,8 +288,12 @@ The `tailwindcss:build` task is automatically attached to the `test:prepare` Rak
 
 ### Building unminified assets
 
-If you want unminified assets, you can pass a `debug` argument to the rake task, i.e. `rails tailwindcss:build[debug]` or `rails tailwindcss:watch[debug]`.
+If you want unminified assets, you can:
 
+- pass a `debug` argument to the rake task, i.e. `rails tailwindcss:build[debug]` or `rails tailwindcss:watch[debug]`.
+- set an environment variable named `TAILWINDCSS_DEBUG` with a non-blank value
+
+If both values are set, the environment variable will take precedence over the rake task argument.
 
 ### Live rebuild
 

lib/tailwindcss/commands.rb

@@ -4,6 +4,7 @@ module Tailwindcss
   module Commands
     class << self
       def compile_command(debug: false, **kwargs)
+        debug = ENV["TAILWINDCSS_DEBUG"].present? if ENV.key?("TAILWINDCSS_DEBUG")
         rails_root = defined?(Rails) ? Rails.root : Pathname.new(Dir.pwd)
 
         command = [

test/lib/tailwindcss/commands_test.rb

@@ -33,6 +33,32 @@ def setup
     end
   end
 
+  test ".compile_command debug environment variable" do
+    begin
+      Rails.stub(:root, File) do # Rails.root won't work in this test suite
+        ENV["TAILWINDCSS_DEBUG"] = ""
+        actual = Tailwindcss::Commands.compile_command
+        assert_kind_of(Array, actual)
+        assert_includes(actual, "--minify")
+
+        actual = Tailwindcss::Commands.compile_command(debug: true)
+        assert_kind_of(Array, actual)
+        assert_includes(actual, "--minify")
+
+        ENV["TAILWINDCSS_DEBUG"] = "any non-blank value"
+        actual = Tailwindcss::Commands.compile_command
+        assert_kind_of(Array, actual)
+        refute_includes(actual, "--minify")
+
+        actual = Tailwindcss::Commands.compile_command(debug: true)
+        assert_kind_of(Array, actual)
+        refute_includes(actual, "--minify")
+      end
+    ensure
+      ENV.delete('TAILWINDCSS_DEBUG')
+    end
+  end
+
   test ".compile_command when Rails compression is on" do
     Rails.stub(:root, File) do # Rails.root won't work in this test suite
       Tailwindcss::Commands.stub(:rails_css_compressor?, true) do