What does mean of variable in javaScript?

Question

javaScript(variable)

var s = s || {};
s.c = {};

what purposes it will be use?

If object is defined, use it. If not then declare empty object. — Tushar, Mar 10 '16 at 11:37
http://stackoverflow.com/questions/35913820/what-does-the-following-code-mean-in-javascript/35913842#35913842 — gurvinder372, Mar 10 '16 at 11:37

score 4 · Answer 1 · answered Mar 10 '16 at 11:38

var s = s || {};

This means that if s is null, undefined or false (it computes to false), then an empty object {} will be assigned to s, so that the second line would not cause an error.

But this notation is inacurate. It should be something like:

var s = (typeof s == 'object') ? s : {};

because in the first example if s is a number the second line will still cause an error.

In the second example notation A ? B : C; is equal to:

if(A){
    B;
}else{
    C;
}

Kindly do not answer dupes... Instead close them. – Praveen Kumar Purushothaman Mar 10 '16 at 11:42 — Praveen Kumar Purushothaman, Mar 10 '16 at 11:42

What does mean of variable in javaScript?

1 Answers1