Question

How do I tell Javascript to use zero as a variable if the passed variable if empty? In PHP I can use the following.

<?php
   function test($var=0){
      echo $var;
   }
?>

So it would set $var to 0 if the passed variable was empty. I can’t seem to figure this out in Javascript.

Thanks

Answer 1

If you call a method without providing a value for one (or more) of the arguments, those arguments will be undefined.

Thus within the method you can test whether the variable is defined, and if not assign it a default value:

function test(arg) {
    if (typeof(arg) === 'undefined') {
        arg = "default"; // or whatever default value you want
    };

    // Rest of method
}

It’s not very elegant, but Javascript doesn’t have a nice native default-arguments syntax.