logical and

Summary

Performs a logical conjunction on two expressions.

Syntax

result = expression1 && expression2

result

Any variable.

expression1

Any expression.

expression2

Any expression.

Examples

console.log(true && true); // true
console.log(true && false); // false
console.log(false && true); // false
console.log(false && (3 == 4); //false
console.log("Cat" && "Dog"); //false
console.log(false && "Cat"); //false
console.log("Cat" && false); //false

Remarks

If both expressions evaluate to true, result is true. If either expression evaluates to false, result is false.

JavaScript uses the following rules for converting non-Boolean values to Boolean values:

• All objects are considered to be true.
• Strings are considered to be false if they are empty.
• null and undefined are considered to be false.
• A Number is false if it is zero.

Attributions

• Microsoft Developer Network: Article