How do you assign default values to variables?

Answer

You can use the logical or operator || in an assignment expression to provide a default value.

Syntax:

var a = b || c;

As per the above expression, variable 'a 'will get the value of 'c' only if 'b' is falsy (if is null, false, undefined, 0, empty string, or NaN), otherwise 'a' will get the value of 'b'.