This function allows you to only call a function if it has everything it needs to run. So it "May" run.

maybe.js

function maybe(fn) {
  return function() {
    var i;
    if ( arguments.length === 0 ) {
      return;
    } else {
      for(i = 0; i < arguments.length; i++) {
        if (arguments[i] == null) return;
      }
      return fn.apply(this, arguments);
    }
  };
}
var empty;
function addOne(num) {
  return num + 1;
}
console.log( maybe(addOne)(empty) );
console.log( maybe(addOne)() );
console.log(maybe( addOne )(1));