Question

I love those short js oneliners. I’d like to know if there’s something logical and elegant for:

• intializing a variable to zero if undefined
• increment by one otherwise.

Shorter than this preferrably 😉

var obj = {} ; 

//some iterative called function
obj.prop = obj.prop===undefined?0:obj.prop++;

Answer 1

This will result in NaN for the first increment, which will default to 0.

obj.prop = ++obj.prop || 0;