feat: switch to using package_json for interacting with package.json

template.rb

@@ -112,6 +112,17 @@ def apply_template! # rubocop:disable Metrics/MethodLength, Metrics/AbcSize, Met
   # but also after `shakapacker:install` and after Rails has initialized the git
   # repo
   after_bundle do
+    require "bundler/inline"
+
+    gemfile do
+      source "https://rubygems.org"
+      gem "package_json", github: "G-Rath/package_json"
+    end
+
+    require "package_json"
+
+    puts "using package_json v#{PackageJson::VERSION}"
+
     # Remove the `test/` directory because we always use RSpec which creates
     # its own `spec/` directory
     remove_dir "test"
@@ -133,7 +144,7 @@ def apply_template! # rubocop:disable Metrics/MethodLength, Metrics/AbcSize, Met
       apply "variants/frontend-bootstrap-typescript/template.rb" if TEMPLATE_CONFIG.apply_variant_bootstrap?
       apply "variants/frontend-react-typescript/template.rb" if TEMPLATE_CONFIG.apply_variant_react?
 
-      run "yarn run typecheck"
+      package_json.manager.run("typecheck")
     end
 
     create_initial_migration
@@ -190,10 +201,14 @@ def apply_template! # rubocop:disable Metrics/MethodLength, Metrics/AbcSize, Met
     # Run the README template at the end because it introspects the app to
     # discover rake tasks etc.
     template "variants/backend-base/README.md.tt", "README.md", force: true
-    run "yarn run prettier --write ./README.md"
+    package_json.manager.run("prettier", ["--write ./README.md"])
   end
 end
 
+def package_json
+  @package_json ||= PackageJson.new(:yarn_classic)
+end
+
 # Normalizes the constraints of the given hash of dependencies so that they
 # all have an explicit constraint and define a minor & patch version
 #
@@ -211,44 +226,45 @@ def normalize_dependency_constraints(deps)
 def build_engines_field
   node_version = File.read("./.node-version").strip
   {
-    node: "^#{node_version}",
-    yarn: "^1.0.0"
+    "node" => "^#{node_version}",
+    "yarn" => "^1.0.0"
   }
 end
 
 def cleanup_package_json
-  package_json = JSON.parse(File.read("./package.json"))
-
-  # ensure that the package name is set based on the folder
-  package_json["name"] = File.basename(__dir__)
-
-  # set engines constraint in package.json
-  package_json["engines"] = build_engines_field
-
-  # ensure that all dependency constraints are normalized
-  %w[dependencies devDependencies].each { |k| package_json[k] = normalize_dependency_constraints(package_json[k]) }
-
-  File.write("./package.json", JSON.pretty_generate(package_json))
+  package_json.merge! do |pj|
+    {
+      "name" => File.basename(__dir__),
+      "engines" => pj.fetch("engines", {}).merge(build_engines_field),
+      "dependencies" => normalize_dependency_constraints(pj.fetch("dependencies", {})),
+      "devDependencies" => normalize_dependency_constraints(pj.fetch("devDependencies", {}))
+    }
+  end
 
   run "npx -y sort-package-json"
-  run "yarn run prettier --write ./package.json"
+
+  package_json.manager.run("prettier", ["--write", "./package.json"])
 
   # ensure the yarn.lock is up to date with any changes we've made to package.json
-  run "yarn install"
+  package_json.manager.install
 end
 
 # Adds the given <code>packages</code> as dependencies using <code>yarn add</code>
 #
 # @param [Array<String>] packages
 def yarn_add_dependencies(packages)
-  run "yarn add #{packages.join " "}"
+  puts "adding #{packages.join(" ")} as dependencies"
+
+  package_json.manager.add(packages)
 end
 
 # Adds the given <code>packages</code> as devDependencies using <code>yarn add --dev</code>
 #
 # @param [Array<String>] packages
 def yarn_add_dev_dependencies(packages)
-  run "yarn add --dev #{packages.join " "}"
+  puts "adding #{packages.join(" ")} as dev dependencies"
+
+  package_json.manager.add(packages, type: :dev)
 end
 
 # Add this template directory to source_paths so that Thor actions like

variants/frontend-base-typescript/template.rb

@@ -27,7 +27,7 @@ def rename_js_file_to_ts(file)
   @typescript-eslint/eslint-plugin@5
 ]
 
-run "yarn install"
+package_json.manager.install
 
 rename_js_file_to_ts "app/frontend/packs/application"
 

variants/frontend-base/js-lint/fixes.rb

@@ -4,5 +4,5 @@
 
 # must be run after prettier is installed and has been configured by setting
 # the 'prettier' key in package.json
-run "yarn run js-lint-fix"
-run "yarn run format-fix"
+package_json.manager.run("js-lint-fix")
+package_json.manager.run("format-fix")

variants/frontend-bootstrap-typescript/template.rb

@@ -2,6 +2,6 @@
 
 yarn_add_dependencies %w[@types/bootstrap]
 
-run "yarn install"
+package_json.manager.install
 
 rename_js_file_to_ts "app/frontend/js/bootstrap"

variants/frontend-bootstrap/template.rb

@@ -1,7 +1,7 @@
 source_paths.unshift(File.dirname(__FILE__))
 
 yarn_add_dependencies(["bootstrap", "@popperjs/core"])
-run "yarn install"
+package_json.manager.install
 
 copy_file "app/frontend/js/bootstrap.js", force: true
 insert_into_file "app/frontend/packs/application.js", "import '../js/bootstrap';", before: "import '../stylesheets/application.scss';"

variants/frontend-react-typescript/template.rb

@@ -2,14 +2,14 @@
 
 installed_jest_major_version = JSON.parse(File.read("node_modules/jest/package.json")).fetch("version").split(".").first
 
-run "yarn remove prop-types"
+package_json.manager.remove(["prop-types"])
 yarn_add_dependencies %w[@types/react @types/react-dom]
 yarn_add_dev_dependencies [
   "@jest/types@#{installed_jest_major_version}",
   "ts-jest@#{installed_jest_major_version}",
   "ts-node"
 ]
-run "yarn install"
+package_json.manager.install
 
 rename_js_file_to_ts "app/frontend/packs/server_rendering"