What is “x && foo()”?

Question

I saw somewhere else said,

x && foo();

　is equal to

if(x){
    foo();
}

I tested it and they really di

Answer 1

In javascript, the && operator evaluates left to right and returns the value of the rightmost operation. If the first condition evaluates to false, it doesn't evaluate the second. So its a shorthand of saying "if something is not null or undefined, do something"