Understanding the “||” OR operator in If conditionals in Ruby

Question

Just briefly, why are the following three lines not identical in their impact?

if @controller.controller_name == \"projects\" || @controller.controller_name          


        

Answer 1

|| is also a null coalescing operator, so

"projects" || "parts"

will return the first string that is not null (in this case "projects"), meaning that in the second two examples, you'll always be evaluating:

if @controller.controller_name == "projects"

Firing up irb, you can check that this is happening:

a = "projects"
b = "parts"

a || b

returns projects