The explanation to "baNaNa" does indicate that the second plus is actually an unary plus operator, which is (in my opinion) key to understanding the trick, yet the reference only lists the binary plus (numeric addition/string concatenation), which is not as important and is a completely different operator.
The explanation to "baNaNa" does indicate that the second plus is actually an unary plus operator, which is (in my opinion) key to understanding the trick, yet the reference only lists the binary plus (numeric addition/string concatenation), which is not as important and is a completely different operator.
Here is the reference to unary plus:
12.5.6 Unary + Operator