JavaScript Logical AND (&&) Operator

Logical AND Operator

logical AND operator takes two operands, and returns true if both left and right operands are true, or false otherwise

&& symbol is used for logical AND operator

a && b

the following truth table provides the output of AND operator for possible operand values

aba && b


1. check if num is positive and an even number

let num = 12;
if ((num > 0) && (num % 2 == 0)) {
    console.log('num is positive and even');
} else {
    console.log('num is either not positive or not even');

in the above example, left operand a is (num > 0) and right operand b is (num % 2 == 0). for given value of num, both a and b are true. if-condition is true, and therefore if-block is run