anchor.diff:  }
   
   main() {
  -  // throttling function calls
  -  var throttle = (fn, delay) {
  -    int timer = 0;
  -    return () => {
  -      fn(context, args);
  -    }
  -  };
  -
     document.on.change.add((event) {
       var api = event.detail.api;
     });
  
positive.code:     if (event.keyCode === 9 || (event.keyCode >= 32 && event.keyCode <= 34 ) || (event.keyCode >= 37 && event.keyCode <= 40)) {
        event.preventDefault();
      }
    })
  
    // trigger impress action (next or prev) on keyup
    document.on.keyUp.add((event) {
  
negative.code: #import('dart:html');
  
  /**
   * Throttling function calls
   */
  throttle(fn, int delay) {
    int handle = 0;
    return (args) {
  