Javascript default parameter

Question

I was reading the Three.js code when a silly question arose: Is there any difference between the codes below?

frameHeight = frameHeight !== undefined ? frameHeight : 24;

and

frameHeight = frameHeight || 24;

(frameHeight is a parameter of the function)

Thanks

Answer 1

Yes, they are different.

frameHeight = frameHeight || 24;

This will coerce frameHeight to a boolean value. If it is 0, '', false, null, undefined, or NaN it will be false and frameHeight will be defaulted to 24.

frameHeight = frameHeight !== undefined ? frameHeight : 24;

This will explicitly check if frameHeight is not undefined and ONLY for undefined will it default it to 24.