Class: TypedViewModel::Base

Inherits:
Literal::Data
  • Object
show all
Defined in:
lib/typed_view_model/base.rb

Overview

Base class for all view model objects Provides common functionality and structure

Class Method Summary collapse

Class Method Details

.__validate_trait_requirements! ⇒ Object

Validates that every name a ‘use`d trait lists in `requires` is available on the host class — either as a declared `prop` or as an instance method. (The trait’s runtime contract is “I will call ‘.foo` on `self`”; the host can satisfy that with either form.) Idempotent and cheap on warm classes — clears the pending list after the first pass so subsequent `.new` calls are a single `defined?` check.



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# File 'lib/typed_view_model/base.rb', line 45

def __validate_trait_requirements!
  return unless defined?(@__used_traits_with_requires)
  return if @__used_traits_with_requires.blank?
  declared = literal_properties.map { |p| p.name.to_sym }.to_set
  @__used_traits_with_requires.each do |trait_module|
    missing = trait_module.required_props.reject do |p|
      sym = p.to_sym
      declared.include?(sym) || method_defined?(sym) || private_method_defined?(sym)
    end
    next if missing.empty?
    raise ArgumentError,
      "TypedViewModel: trait `#{trait_module.name || trait_module.inspect}` " \
      "requires #{missing.inspect} on host class `#{name || inspect}` but neither " \
      "a declared `prop` nor an instance method matches. Add the missing prop/method " \
      "or remove the entry from the trait's `requires` declaration."
  end
  @__used_traits_with_requires = nil
end

.helpers(*names) ⇒ Object

DSL for including helper modules. Looks up ‘“#NameHelpers”` in each module listed in `TypedViewModel.helper_namespaces`. Host apps can register their own namespaces:

TypedViewModel.helper_namespaces << MyApp::ViewModelHelpers

Usage:

helpers :i18n, :path, :format



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# File 'lib/typed_view_model/base.rb', line 78

def helpers(*names)
  names.each do |name|
    helper_class_name = "#{name.to_s.camelize}Helpers"
    helper_module = nil
    ::TypedViewModel.helper_namespaces.each do |ns|
      ns_module = resolve_helper_namespace(ns)
      next unless ns_module.const_defined?(helper_class_name, false)
      helper_module = ns_module.const_get(helper_class_name, false)
      break
    end
    unless helper_module
      searched = ::TypedViewModel.helper_namespaces.map { |ns| ns.is_a?(::String) ? ns : ns.name }.join(", ")
      raise ArgumentError,
        "Unknown helper: #{name}. Searched: #{searched}"
    end
    include helper_module
  end
end

.new ⇒ Object 



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# File 'lib/typed_view_model/base.rb', line 64

def new(...)
  __validate_trait_requirements!
  super
end

.use(trait_module) ⇒ Object

Use a trait module that provides model-specific presentation logic. Records the trait so we can validate on first instantiation that every prop the trait ‘requires` is declared on the host class. Validation is deferred to `new` because the conventional pattern is `use Foo` before `prop :bar` — class-define-time validation would false-positive on every VM that follows that ordering.



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# File 'lib/typed_view_model/base.rb', line 31

def use(trait_module)
  include trait_module

  if trait_module.respond_to?(:required_props) && trait_module.required_props.any?
    (@__used_traits_with_requires ||= []) << trait_module
  end
end