Example: A sample function

  function sayHi($value = '') {
  
    return $value;
  
  } 
                  

The function above will be tested by the @onhide() to know if the returned value is empty. If an empty value is returned, then the attribute "hidden" will be added to the html element. A sample is shown below

  <div @onhide('sayHi')>  
  
  some text here
  
  </div>
                  

These above will resolve as

  <div hidden="hidden">  
  
  some text here
  
  </div>
                  

The "hidden" attribute was added because the function returned a an empty value. No attribute will be added if a value was returned by the function. If we need to supply any argument to this directive, the arguments should come after the first argument which function name.