Improve lines insertion in installers

[ricardotk002]

Maintaining empty strings at the beginning of each line to be inserted can be error prone (eg. #1422). In this contribution I'm using the optimize_indentation method from Rails::Generators to insert lines, this helps to indent the lines and add the line breaks automatically. Rails uses this very often on their generators.

I also wanted to add some tests for the installers, but since they do more than generators I don't know where to start. Any help will be appreciated.

[grk]

The optimize_indentation method is available only in Rails 5.2+, so unless the aim is to only support latest Rails, this change should be reverted.

[gauravtiwari]

//cc @guilleiguaran

[ricardotk002]

@guilleiguaran @grk I'm really sorry about this, I didn't notice that this method was too new.

What do you think about using the String#indent directly instead of the helper?

diff --git a/lib/install/coffee.rb b/lib/install/coffee.rb
index aa19835..ef8f65f 100644
--- a/lib/install/coffee.rb
+++ b/lib/install/coffee.rb
@@ -13,7 +13,7 @@ insert_into_file Rails.root.join("config/webpack/environment.js").to_s,
   before: "module.exports"
 
 say "Updating webpack paths to include .coffee file extension"
-insert_into_file Webpacker.config.config_path, optimize_indentation("- .coffee", 4), after: /extensions:\n/
+insert_into_file Webpacker.config.config_path, "- .coffee\n".indent(4), after: /extensions:\n/
 
 say "Copying the example entry file to #{Webpacker.config.source_entry_path}"
 copy_file "#{__dir__}/examples/coffee/hello_coffee.coffee",
diff --git a/lib/install/elm.rb b/lib/install/elm.rb
index 984d09f..d3803d7 100644
--- a/lib/install/elm.rb
+++ b/lib/install/elm.rb
@@ -26,7 +26,7 @@ run "yarn add --dev elm-hot-loader"
 run "yarn run elm package install -- --yes"
 
 say "Updating webpack paths to include .elm file extension"
-insert_into_file Webpacker.config.config_path, optimize_indentation("- .elm", 4), after: /extensions:\n/
+insert_into_file Webpacker.config.config_path, "- .elm\n".indent(4), after: /extensions:\n/
 
 say "Updating Elm source location"
 gsub_file "elm-package.json", /\"\.\"\n/,
diff --git a/lib/install/erb.rb b/lib/install/erb.rb
index 9fb8843..08c1dfa 100644
--- a/lib/install/erb.rb
+++ b/lib/install/erb.rb
@@ -13,7 +13,7 @@ insert_into_file Rails.root.join("config/webpack/environment.js").to_s,
   before: "module.exports"
 
 say "Updating webpack paths to include .erb file extension"
-insert_into_file Webpacker.config.config_path, optimize_indentation("- .erb", 4), after: /extensions:\n/
+insert_into_file Webpacker.config.config_path, "- .erb\n".indent(4), after: /extensions:\n/
 
 say "Copying the example entry file to #{Webpacker.config.source_entry_path}"
 copy_file "#{__dir__}/examples/erb/hello_erb.js.erb",
diff --git a/lib/install/react.rb b/lib/install/react.rb
index 299ea8e..0491fab 100644
--- a/lib/install/react.rb
+++ b/lib/install/react.rb
@@ -23,7 +23,7 @@ say "Copying react example entry file to #{Webpacker.config.source_entry_path}"
 copy_file "#{__dir__}/examples/react/hello_react.jsx", "#{Webpacker.config.source_entry_path}/hello_react.jsx"
 
 say "Updating webpack paths to include .jsx file extension"
-insert_into_file Webpacker.config.config_path, optimize_indentation("- .jsx", 4), after: /extensions:\n/
+insert_into_file Webpacker.config.config_path, "- .jsx\n".indent(4), after: /extensions:\n/
 
 say "Installing all react dependencies"
 run "yarn add react react-dom babel-preset-react prop-types"
diff --git a/lib/install/template.rb b/lib/install/template.rb
index 5867804..9dc2738 100644
--- a/lib/install/template.rb
+++ b/lib/install/template.rb
@@ -17,7 +17,7 @@ apply "#{__dir__}/binstubs.rb"
 
 say "Adding configurations"
 
-check_yarn_integrity_config = ->(value) { <<CONFIG }
+check_yarn_integrity_config = ->(value) { <<CONFIG.indent(2) }
 # Verifies that versions and hashed value of the package contents in the project's package.json
 config.webpacker.check_yarn_integrity = #{value}
 CONFIG
@@ -26,18 +26,18 @@ if Rails::VERSION::MAJOR >= 5
   environment check_yarn_integrity_config.call("true"), env: :development
   environment check_yarn_integrity_config.call("false"), env: :production
 else
-  inject_into_file "config/environments/development.rb", optimize_indentation(check_yarn_integrity_config.call("true"), 2), after: "Rails.application.configure do", verbose: false
-  inject_into_file "config/environments/production.rb", optimize_indentation(check_yarn_integrity_config.call("false"), 2), after: "Rails.application.configure do", verbose: false
+  inject_into_file "config/environments/development.rb", "\n#{check_yarn_integrity_config.call("true")}", after: "Rails.application.configure do", verbose: false
+  inject_into_file "config/environments/production.rb", "\n#{check_yarn_integrity_config.call("false")}", after: "Rails.application.configure do", verbose: false
 end
 
 if File.exists?(".gitignore")
-  append_to_file ".gitignore", optimize_indentation(<<-EOS)
-    /public/packs
-    /public/packs-test
-    /node_modules
-    yarn-debug.log*
-    .yarn-integrity
-  EOS
+  append_to_file ".gitignore", <<-EOS
+/public/packs
+/public/packs-test
+/node_modules
+yarn-debug.log*
+.yarn-integrity
+EOS
 end
 
 say "Installing all JavaScript dependencies"
diff --git a/lib/install/typescript.rb b/lib/install/typescript.rb
index 187f08a..cd2391f 100644
--- a/lib/install/typescript.rb
+++ b/lib/install/typescript.rb
@@ -31,10 +31,10 @@ say "Copying tsconfig.json to the Rails root directory for typescript"
 copy_file "#{__dir__}/examples/#{example_source}/tsconfig.json", "tsconfig.json"
 
 say "Updating webpack paths to include .ts file extension"
-insert_into_file Webpacker.config.config_path, optimize_indentation("- .ts", 4), after: /extensions:\n/
+insert_into_file Webpacker.config.config_path, "- .ts\n".indent(4), after: /extensions:\n/
 
 say "Updating webpack paths to include .tsx file extension"
-insert_into_file Webpacker.config.config_path, optimize_indentation("- .tsx", 4), after: /extensions:\n/
+insert_into_file Webpacker.config.config_path, "- .tsx\n".indent(4), after: /extensions:\n/
 
 say "Copying the example entry file to #{Webpacker.config.source_entry_path}"
 copy_file "#{__dir__}/examples/typescript/hello_typescript.ts",
diff --git a/lib/install/vue.rb b/lib/install/vue.rb
index b770cb8..c345d2e 100644
--- a/lib/install/vue.rb
+++ b/lib/install/vue.rb
@@ -22,7 +22,7 @@ insert_into_file Rails.root.join("config/webpack/environment.js").to_s,
   before: "module.exports"
 
 say "Updating webpack paths to include .vue file extension"
-insert_into_file Webpacker.config.config_path, optimize_indentation("- .vue", 4), after: /extensions:\n/
+insert_into_file Webpacker.config.config_path, "- .vue\n".indent(4), after: /extensions:\n/
 
 say "Copying the example entry file to #{Webpacker.config.source_entry_path}"
 copy_file "#{__dir__}/examples/vue/hello_vue.js",

I tried introducing a new helper that would mimic #optimize_indentation, but that seemed too much for a simple change.

I hope this helps, otherwise let me know and I can revert the commits I introduced.

[guilleiguaran]

@ricardotk002 please send a PR replacing optimize_indentation with String#indent

[ricardotk002]

@guilleiguaran Sure! I submitted #1468 and ensured that we won't have this issue again. Thank you all for your help.