Class: JsxRosetta::Backend::ViewComponent

Inherits:
Base
  • Object
show all
Defined in:
lib/jsx_rosetta/backend/view_component.rb,
lib/jsx_rosetta/backend/view_component/expression_translator.rb

Overview

Emits a Rails ViewComponent (one Ruby class + one ERB template) from an IR::Component.

Phase 3 scope:

- Single component per emit.
- JSX prop names lowered to snake_case Ruby kwargs and matching
  `@instance_variable` assignments.
- JS expressions translated via ExpressionTranslator where the
  shape is recognized; otherwise emitted as a TODO marker plus
  verbatim source.
- HTML attributes emitted directly; className / template-literal
  class expressions inlined into the `class="..."` attribute.

Phase 4a additions:

- `children` prop is treated as ViewComponent's default content
  slot: it's filtered out of the initializer and rendered as
  `<%= content %>` wherever the IR has IR::Slot(name: "children").
- IR::Conditional renders as `<% if %>...<% else %>...<% end %>`.

Direct Known Subclasses

RailsView

Defined Under Namespace

Classes: EventDescriptor, ExpressionTranslator

Constant Summary collapse

DEFAULT_SLOT_NAME = 
"children"
VOID_ELEMENTS = 
%w[area base br col embed hr img input link meta param source track wbr].freeze
DEFAULT_HELPERS =

JSX component names that have a direct Rails view-helper analog. Override per-instance via ‘ViewComponent.new(helpers: …)`, or disable by passing `helpers: false`.

{
  "Link" => { method: :link_to, positional: :href }.freeze,
  "Image" => { method: :image_tag, positional: :src }.freeze
}.freeze
HOOK_TODO_HEADERS =

Per-library TODO header lines surfaced above the verbatim hook source. Each library has a different Rails analog, so we don’t collapse them into a single generic block. Keys must mirror the ‘:library` values produced by IR::Lowering. First line is rendered with the `<%#` opener; subsequent lines are indented continuation.

{
  react: [
    "TODO: React hooks detected. None translate automatically. Hotwire/Stimulus",
    "handles behavior; controllers/views handle state; turbo-frames handle async",
    "loading. Original source:"
  ].freeze,
  apollo: [
    "TODO: Apollo data-fetching hooks detected. None translate automatically.",
    "Move the fetch to the Rails controller (or a model/service); pass the",
    "result in as a prop. For useMutation, use a form POST + redirect or a",
    "Turbo Stream response. Original source:"
  ].freeze,
  next_js: [
    "TODO: Next.js navigation hooks detected. None translate automatically.",
    "Rails analogs: useRouter -> redirect_to / form actions;",
    "usePathname -> request.path; useSearchParams / useParams -> params;",
    "useSelectedLayoutSegment(s) -> match against request.path in the view.",
    "Original source:"
  ].freeze
}.freeze

Instance Method Summary collapse

Constructor Details

#initialize(helpers: nil, layout: :sidecar) ⇒ ViewComponent

Returns a new instance of ViewComponent.



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# File 'lib/jsx_rosetta/backend/view_component.rb', line 71

def initialize(helpers: nil, layout: :sidecar)
  super()
  @helpers = case helpers
             when nil then DEFAULT_HELPERS
             when false then {}
             else helpers
             end
  unless %i[sidecar flat].include?(layout)
    raise ArgumentError, "unknown layout: #{layout.inspect} (expected :sidecar or :flat)"
  end

  @layout = layout
end

Instance Method Details

#class_name_for(component) ⇒ Object 



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# File 'lib/jsx_rosetta/backend/view_component.rb', line 137

def class_name_for(component)
  component.name[0].upcase + component.name[1..]
end

#data_factory_signature(method_name, param_names) ⇒ Object 



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# File 'lib/jsx_rosetta/backend/view_component.rb', line 141

def data_factory_signature(method_name, param_names)
  return method_name if param_names.empty?

  kwargs = param_names.map { |name| "#{AST::Inflector.underscore(name)}: nil" }
  "#{method_name}(#{kwargs.join(", ")})"
end

#emit(component) ⇒ Object 



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# File 'lib/jsx_rosetta/backend/view_component.rb', line 85

def emit(component)
  translator = build_translator(component)
  base_name = "#{AST::Inflector.underscore(component.name)}_component"
  @stimulus_identifier = component.stimulus_methods.any? ? stimulus_identifier(component) : nil

  # Data-factory components (column-descriptor modules) have no
  # template — they're pure-data classes. Skip the .erb pair and
  # emit a single .rb with the factory method. JSX render lambdas
  # inside the data have nowhere to live in the ViewComponent
  # ERB-template world, so we surface a TODO note in the class.
  return emit_data_factory(component) if component.mode == :data_factory

  files = [
    File.new(path: "#{base_name}.rb", contents: render_ruby_class(component, translator)),
    File.new(path: erb_path(base_name), contents: render_erb_template(component, translator))
  ]
  if component.stimulus_methods.any?
    files << File.new(
      path: stimulus_path(component, base_name),
      contents: render_stimulus_controller_js(component)
    )
  end
  files
end

#emit_data_factory(component) ⇒ Object

For data-factory components emit a plain Ruby class (no ApplicationViewComponent base, no ERB template). The user can mix it into a ViewComponent or call the method directly — the goal is to surface the translated data array, not to render it in isolation.



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# File 'lib/jsx_rosetta/backend/view_component.rb', line 114

def emit_data_factory(component)
  method_name = AST::Inflector.underscore(component.name)
  param_names = component.props.map(&:name)
  translator = ExpressionTranslator.new(prop_names: [], local_binding_names: param_names)
  signature = data_factory_signature(method_name, param_names)
  body = translator.with_locals(param_names) do
    inline_render_value(component.body, translator, indent: 4)
  end
  contents = <<~RUBY
    # frozen_string_literal: true

    # TODO: data-factory module — the translated array contains JSX render
    # lambdas as `nil` placeholders. Wire each up to a Phlex helper or a
    # method on the consuming ViewComponent.
    class #{class_name_for(component)}
      def #{signature}
        #{body}
      end
    end
  RUBY
  [File.new(path: "#{AST::Inflector.underscore(component.name)}.rb", contents: contents)]
end

#erb_path(base_name) ⇒ Object 



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# File 'lib/jsx_rosetta/backend/view_component.rb', line 189

def erb_path(base_name)
  @layout == :sidecar ? "#{base_name}/#{base_name}.html.erb" : "#{base_name}.html.erb"
end

#inline_render_value(value, translator, indent: 0) ⇒ Object

Recursively render a non-JSX value (ObjectLiteral / ArrayLiteral / Lambda / Interpolation / primitives) without the kwarg-list context the Phlex backend uses. IR::Lambda and unmatched cases both fall through to ‘nil` — there’s no Phlex class to host a rendered method body, and the class-level TODO comment above the emitted file already flags both for the reviewer.



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# File 'lib/jsx_rosetta/backend/view_component.rb', line 154

def inline_render_value(value, translator, indent: 0)
  case value
  when IR::ObjectLiteral then render_factory_object_literal(value, translator, indent: indent)
  when IR::ArrayLiteral then render_factory_array_literal(value, translator, indent: indent)
  when IR::Interpolation then translator.translate(value.expression)&.ruby || "nil"
  when String then value.inspect
  when true then "true"
  else "nil"
  end
end

#render_factory_array_literal(arr, translator, indent:) ⇒ Object 



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# File 'lib/jsx_rosetta/backend/view_component.rb', line 178

def render_factory_array_literal(arr, translator, indent:)
  parts = arr.elements.map do |el|
    el.nil? ? "nil" : inline_render_value(el, translator, indent: indent + 2)
  end
  return "[]" if parts.empty?

  pad = " " * (indent + 2)
  close_pad = " " * indent
  "[\n#{pad}#{parts.join(",\n#{pad}")}\n#{close_pad}]"
end

#render_factory_object_literal(obj, translator, indent:) ⇒ Object 



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# File 'lib/jsx_rosetta/backend/view_component.rb', line 165

def render_factory_object_literal(obj, translator, indent:)
  parts = obj.properties.map do |(key, value)|
    rendered = inline_render_value(value, translator, indent: indent + 2)
    snake = AST::Inflector.underscore(key)
    if snake.match?(/\A[a-z_][a-z0-9_]*\z/)
      "#{snake}: #{rendered}"
    else
      "#{key.inspect} => #{rendered}"
    end
  end
  "{ #{parts.join(", ")} }"
end

#render_stimulus_controller_js(component) ⇒ Object 



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# File 'lib/jsx_rosetta/backend/view_component.rb', line 202

def render_stimulus_controller_js(component)
  lines = [
    'import { Controller } from "@hotwired/stimulus";',
    "",
    "export default class extends Controller {"
  ]
  component.stimulus_methods.each_with_index do |method, idx|
    lines << "" if idx.positive?
    lines.concat(stimulus_method_lines(method))
  end
  lines << "}"
  "#{lines.join("\n")}\n"
end

#stimulus_identifier(component) ⇒ Object 



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# File 'lib/jsx_rosetta/backend/view_component.rb', line 198

def stimulus_identifier(component)
  AST::Inflector.underscore(component.name).tr("_", "-")
end

#stimulus_method_lines(method) ⇒ Object 



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# File 'lib/jsx_rosetta/backend/view_component.rb', line 216

def stimulus_method_lines(method)
  body_lines = method.body_source.strip.split("\n")
  commented = body_lines.map { |line| "  //   #{line}" }
  header = ["  // TODO: translate from the original JSX handler:"]
  if method.name != method.original_name
    header.unshift("  // NOTE: method renamed from #{method.original_name.inspect} " \
                   "to avoid collision with an earlier handler")
  end
  header + commented + [
    "  #{method.name}(event) {",
    "    // ...",
    "  }"
  ]
end

#stimulus_path(component, base_name) ⇒ Object 



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# File 'lib/jsx_rosetta/backend/view_component.rb', line 193

def stimulus_path(component, base_name)
  controller_filename = "#{AST::Inflector.underscore(component.name)}_controller.js"
  @layout == :sidecar ? "#{base_name}/#{controller_filename}" : controller_filename
end