module RespondToDig

Extracts the nested value specified by the sequence of index by calling dig at each step, returning nil if any intermediate step is nil. @example

h = RespondToDig.invoke({ foo: {bar: {baz: 1 }}})
h.dig(:foo, :bar, :baz)           #=> 1
h.dig(:foo, :zot, :xyz)           #=> nil
h.dig(:foo, :bar, :baz, :xyz)     #=> TypeError

g = RespondToDig.invoke({ foo: [10, 11, 12] })
g.dig(:foo, 1)                    #=> 11

Constants

VERSION

Public Class Methods

diggable?(target) click to toggle source

Returns whether the ‘target` object is able to be invoked by `RespondToDig` @note The reason why not purely duck typed by `[]` method is to avoid unexpected behavior,

for example we won't get `'o'` by `'foo'.dig(1)` by String#[].

@param target [Object] @return [Bool]

# File lib/respond_to_dig.rb, line 29
def diggable?(target)
  target.is_a? Enumerable and
      target.respond_to? :[] and
      not target.respond_to? :dig
end

invoke(receiver)

Alias for: respond_to_dig

invoke_dig(receiver)

@deprecated Please use {#invoke} instead

Alias for: respond_to_dig

respond_to_dig(receiver) click to toggle source

Invokes ‘RespondToDig` module if the `receiver` object is digabble @see RespondToDig#digabble @param receiver [Object] @return [Object, RespondToDig]

# File lib/respond_to_dig.rb, line 18
def respond_to_dig(receiver)
  receiver.tap do |r|
    r.singleton_class.send(:include, RespondToDig) if RespondToDig.diggable? r
  end
end

Also aliased as: invoke_dig, invoke

Public Instance Methods

dig(key, *rest) click to toggle source

Retrieves the value object corresponding to the each ‘key` objects recursively with nil-safe @param key [Object, …] @raise [TypeError] Throws if trying to access the value which doesn’t respond to ‘#dig` such as `String` object @return [Object, RespondToDig, NilClass]

# File lib/respond_to_dig.rb, line 44
def dig(key, *rest)
  value = RespondToDig.invoke(self[key])
  if value.nil? || rest.empty?
    value
  elsif value.respond_to?(:dig)
    value.dig(*rest)
  else
    fail TypeError, "#{value.class} does not have #dig method"
  end
end