diff options
Diffstat (limited to 'activesupport/lib/active_support/core_ext')
-rw-r--r-- | activesupport/lib/active_support/core_ext/object/try.rb | 33 |
1 files changed, 25 insertions, 8 deletions
diff --git a/activesupport/lib/active_support/core_ext/object/try.rb b/activesupport/lib/active_support/core_ext/object/try.rb index 09b8a19789..0bc675329d 100644 --- a/activesupport/lib/active_support/core_ext/object/try.rb +++ b/activesupport/lib/active_support/core_ext/object/try.rb @@ -9,7 +9,23 @@ class Object # # instead of # - # @person ? @person.name : nil + # @person.name if @person + # + # +try+ calls can be chained: + # + # @person.try(:spouse).try(:name) + # + # instead of + # + # @person.spouse.name if @person && @person.spouse + # + # +try+ will also return +nil+ if the receiver does not respond to the method: + # + # @person.try(:non_existing_method) + # + # instead of + # + # @person.non_existing_method if @person.respond_to?(:non_existing_method) # # +try+ returns +nil+ when called on +nil+ regardless of whether it responds # to the method: @@ -24,7 +40,7 @@ class Object # # The number of arguments in the signature must match. If the object responds # to the method the call is attempted and +ArgumentError+ is still raised - # otherwise. + # in case of argument mismatch. # # If +try+ is called without arguments it yields the receiver to a given # block unless it is +nil+: @@ -38,17 +54,18 @@ class Object # # @person.try { upcase.truncate(50) } # - # Please also note that +try+ is defined on +Object+, therefore it won't work + # Please also note that +try+ is defined on +Object+. Therefore, it won't work # with instances of classes that do not have +Object+ among their ancestors, # like direct subclasses of +BasicObject+. For example, using +try+ with # +SimpleDelegator+ will delegate +try+ to the target instead of calling it on - # delegator itself. + # the delegator itself. def try(*a, &b) try!(*a, &b) if a.empty? || respond_to?(a.first) end - # Same as #try, but will raise a NoMethodError exception if the receiving is not nil and + # Same as #try, but will raise a NoMethodError exception if the receiver is not +nil+ and # does not implement the tried method. + def try!(*a, &b) if a.empty? && block_given? if b.arity.zero? @@ -64,15 +81,15 @@ end class NilClass # Calling +try+ on +nil+ always returns +nil+. - # It becomes specially helpful when navigating through associations that may return +nil+. + # It becomes especially helpful when navigating through associations that may return +nil+. # # nil.try(:name) # => nil # # Without +try+ - # @person && !@person.children.blank? && @person.children.first.name + # @person && @person.children.any? && @person.children.first.name # # With +try+ - # @person.try(:children).try(:first).try(:name) + # @person.try(:children).first.try(:name) def try(*args) nil end |