Using conditional operator to indicate if value exists

Question

I have variable named objectId.The objectId contains some string number.

In this row I try to check wether some value exists in objectId:

   self.showObjects = self.objectId == true ? true : false;

But even if value exists the showObjects get false.

Any idea how to fix the row to make ot work properly?

what values can `self.objectId` have? is zero possible? or an empty string? — Nina Scholz, Oct 06 '16 at 19:01
You want a simple `!! self.objectId` or `Boolean(self.objectId)`. No need to use a conditional operator. — Bergi, Oct 06 '16 at 19:03

Sushanth -- · Accepted Answer · 2016-10-06T19:03:53.083

4

You could use

self.showObjects = !!self.objectId;

The use of double not will coerce the value to a boolean, which will always get converted to truthy or falsy values.

!!0 
!!""
!!false
!!NaN

All operations return false.

Any other non empty value will give you true.

edited Oct 06 '16 at 19:03

answered Oct 06 '16 at 18:58

Sushanth --

You can simply link to http://stackoverflow.com/q/784929/1048572. No need to explain everything again here :-) – Bergi Oct 06 '16 at 19:05

1 Answers1