JavaScript short-circuit expression

Short-circuit expression: as "&&" and "| |" Operator's operand expression, which is evaluated as long as the final result can be determined to be true or FALSE, the evaluation process terminates, which is called a short-circuit evaluation. This is an important property of these two operators.

Code:

1         // || (If a has a value then take a, and vice versa, take B)2         varFoo = a | |b;3         //equivalent4         if(a) {5Foo =A;6}Else {7Foo =b;8         }9 Ten         //&& (If a has a value then take B and vice versa) One         varBar = a &&b; A         //equivalent -         if(a) { -Bar =b; the}Else { -Bar =A; -}

Using this kind of short-circuit expression can make the code look concise and improve the coding efficiency.

JavaScript short-circuit expression