Let's say we have a variable that we expect to be a hash, but could also be
nil. We want to try to grab a value from that hash by referencing a specific
key. Because it could be nil, we cannot simply do:
stuff[:key]As that could result in NoMethodError: undefined method '[]' for nil (NoMethodError).
We should use the safe navigation operator (&) to avoid raising that error.
However, we should pay attention to a necessary syntax shift from the short-hand
[:key] to the long-hand [](:key).
stuff&.[](:key)The meaning of this syntax is that we are calling the #[] method and we pass
it a single argument :key wrapped in parentheses.
Another approach would be to use #dig which can feel more ergonomic than the
above syntax switch.
stuff&.dig(:key)