The Object#try method in Rails

2015-02-17

Say you’re in Rails and want check that a method exists & that it is not nil:

my_object.my_method

One way you could do this is:

if my_object
  if my_object.my_method
    my_object.my_method
  end
end

If you were cleverer, you could just do:

if my_object && my_object.my_method
    my_object.my_method
    ...

The trouble with these approaches is they can become cumbersome:

if my_object &&
   my_object.my_method &&
    my_object.my_method.my_second_method

my_object.my_method.my_second_method

And that’s using the more concise syntax… A better approach would be to use the Object#try method. It ‘tries’ an object’s method and, instead of going mental, calmly returns nil if that method doesn’t work.

my_object.try(:my_method)

Ta da! This makes the more nested existence-validations read much better:

my_object.try(:my_method).try(:my_second_method)

If you’re using standard ruby, the #defined? and #nil? methods could help…

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