Question

I have 3 variables, that are not always set. o1, o2, o3.

I want to create a new variable as follows:

if none are set: o4 = null

if o1 is set, o4 = o1, regarded of what the other are.

when o1 is not set and o2 is set: o4 = o2

So o4 = o3 only gets set when 1 and 2 are not set.

==

I am now using a long switch, but I bet it can be done better.

JavaScript / jQuery

    var tmpl = '';

    if(data.o3 != null)
        tmpl = data.o3;

    if(data.o2 != null)
        tmpl = data.o2;

    if(data.o1 != null)
        tmpl = data.o1;

Answer 1

Try var o4 = o1 || o2 || o3.

Edit: As per comments, this only works when values that might be set are not falsy. May be best to avoid this method, unless you’re sure.