nil‘s in Ruby can be annoying. Thankfully, Ruby version 2.3.0 gave us a safe navigation operator, something that other languages like C# and Swift already had. It’s very much like ActiveSupport’s try method, which checks if a receiver responds to a method before calling that method. If the receive doesn’t respond to the method, nil is returned.
Usage
Here is a trivial example to demonstrate how this works. Let’s say you need to call upcase an object attribute that may or may not be defined. At some point, this might happen:
person = Struct.new(:first_name) bob = person.new => #<struct first_name=nil> bob.first_name.upcase # => undefined method `upcase' for nil:NilClass
Before Ruby 2.3.0, we might have solved this problem with something like:
bob.first_name.upcase if bob.first_name => nil
Using the Safe Navigation Operator (&.) we can do this:
bob.first_name&.upcase => nil
In this example, calling first_name on the bob instance returns nil, so &. halts the method chain right there.