Rails ViewComponent convenience, e.g. `c.heading("Hi")`

0_example.erb

Before:
<%= render Admin::HeadingComponent.new("Hi") %>

After:
<%= c.heading "Hi" %>

admin_base_helper.rb

module Admin::BaseHelper
  def c
    @component_renderer ||= ComponentRenderer.new(self, namespace: Admin)
  end
end

component_renderer.rb

# E.g. in app/lib.

class ComponentRenderer
  def initialize(view_context, namespace: Object)
    @view_context = view_context
    @namespace = namespace
  end

  def method_missing(name, ...)
    const_name = build_const_name(name)
    return super unless @namespace.const_defined?(const_name)

    # For performance (TODO: measure), we define a method the first time. It won't be missing on the next call on the same (presumed memoized) instance.
    klass = @namespace.const_get(const_name)
    define_singleton_method(name) do |*args, **kwargs, &block|
      @view_context.render(klass.new(*args, **kwargs), &block)
    end

    public_send(name, ...)
  end

  def respond_to_missing?(name, _include_private = false)
    const_name = build_const_name(name)
    @namespace.const_defined?(const_name) || super
  end

  private

  def build_const_name(name) = name.to_s.camelize + "Component"
end