JSON Template

1model_example.rb

@model = OpenStruct.new(name: 'steve', age: 12, contacts: [{name: 'steve', sekret: 6}], other: 'stuff', moar: 'things')

json @model,
  :name,
  :age,
  oldness: :age,
  friends: [nested(:name), from: :contacts],
  contacts: nested('contact_partial', :model)
  other: ->(c) { c + 'hai' },
  stuff: [->(c) { c + 'you' }, from: :moar]

2array_example.rb

json [@model],
  this: :name

2wrapped_array_example.rb

{people: (json [@model],
  this: :name
)}

4implementation.rb

def get_or_map(k, v, object)
  if v.respond_to?(:call)
    v.call(object.public_send(k))
  elsif v.is_a?(Array)
    v.last.call(object.public_send(v.first))
  else
    object.public_send(v)
  end
end

def nested(*args)
  lambda do |*largs|
    if largs.first.is_a?(String)
      # Get partial and render
    else
      json(largs.first, *args)
    end
  end
end

def json(*args)
  object = args.shift
  object = OpenStruct.new(object) if object.is_a?(Hash)
  if object.respond_to?(:map)
    object.map { |x| json(x, *args) }
  else
    extra = args.last.is_a?(Hash) ? args.pop : {}
    h = args.each_with_object({}) do |k, h|
      h[k] = get_or_map(k, k, object)
    end
    extra.each_with_object(h) do |(k, v), h|
      h[k] = get_or_map(k, v, object)
    end
  end
end