class GraphQL::Directive


- ‘@include(if: …)` Includes the tagged field only if `if` is true
- `@skip(if: …)` Skips the tagged field if the value of `if` is true
Two directives are included out-of-the-box:
Directives are server-defined hooks for modifying execution.

def include?(arguments) 

def include?(arguments)
  include_proc.call(arguments)
end

def initialize 

def initialize
  @arguments = {}
end

def on_field? 

def on_field?
  locations.include?(FIELD)
end

def on_fragment? 

def on_fragment?
  locations.include?(FRAGMENT_SPREAD) && locations.include?(INLINE_FRAGMENT)
end

def on_operation? 

def on_operation?
  locations.include?(QUERY) && locations.include?(MUTATION) && locations.include?(SUBSCRIPTION)
end

def to_s 

def to_s
  "<GraphQL::Directive #{name}>"
end