How to check if a variable is null or empty string or all whitespace in JavaScript?

Question

I need to check to see if a variable is null or has all empty spaces or is just blank (\"\").

I have the following, but it is not working:

var addr;
         


        

Answer 1

Simplified version of the above: (from here: https://stackoverflow.com/a/32800728/47226)

function isNullOrWhitespace( input ) {
  return !input || !input.trim();
}