class RuboCop::Cop::Lint::ToJSON

Checks to make sure `#to_json` includes an optional argument. When overriding `#to_json`, callers may invoke JSON generation via `JSON.generate(your_obj)`. Since `JSON#generate` allows for an optional argument, your method should too.

@example

class Point
  attr_reader :x, :y

  # bad, incorrect arity
  def to_json
    JSON.generate([x, y])
  end

  # good, preserving args
  def to_json(*args)
    JSON.generate([x, y], *args)
  end

  # good, discarding args
  def to_json(*_args)
    JSON.generate([x, y])
  end
end

Constants

MSG

Public Instance Methods

on_def(node) click to toggle source
# File lib/rubocop/cop/lint/to_json.rb, line 36
def on_def(node)
  return unless node.method?(:to_json) && node.arguments.empty?

  add_offense(node) do |corrector|
    # The following used `*_args` because `to_json(*args)` has
    # an offense of `Lint/UnusedMethodArgument` cop if `*args`
    # is not used.
    corrector.insert_after(node.loc.name, '(*_args)')
  end
end