fetch(key, *args)
Instance Public methods
Returns a parameter for the given key. If the key
can't be found, there are several options: With no other arguments, it
will raise an ActionController::ParameterMissing error; if
more arguments are given, then that will be returned; if a block is given,
then that will be run and its result returned.
params = ActionController::Parameters.new(person: { name: 'Francesco' })
params.fetch(:person) # => {"name"=>"Francesco"}