What does the '&&' expression mean in this snippet of JavaScript? [closed]

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Closed 9 years ago.

Hi, I recently got a piece of JavaScript code snippet from here.

Could someone please explain how this statement works: (jq=jq.slice(1)).length && hidenext(jq);in the function below?

(function hidenext(jq){
    jq.eq(0).fadeOut("fast", function(){
        (jq=jq.slice(1)).length && hidenext(jq);
    });
})($('div#bodyContent a'))

Answer 1

Here, as the result isn't used, the logical AND is used as a kind of short if.

It's the same as

if ((jq=jq.slice(1)).length) hidenext(jq);

It uses the fact that the second part won't be evaluated if the first one doesn't evaluate as true.

Answer 2

It means that hidenext(jq) will only be called if jq (now set to the return value of jq.slice(1) has a length > 0. Because && is short-circuited, evaluation is halted if the first operand is falsy.