text: 
  // switch
  
  var i = 30;
  switch (i)
  {
      case 10:
          console.log('10');
          break;
      case 15:
      case 20:
          console.log('15 or 20');
          break;
      case 30:
          console.log('30');
          break;
      default:
          console.log('unknown');
  }
  
  switch ('hello world')
  {
      case 'hello' + ' world':
          console.log('Greeting was found.');
          break;
      case 'goodbye':
          console.log('Closing was found.');
          break;
      default:
          console.log('Unkown');
  }
  
  var num = 25;
  switch (true)
  {
      case num < 0:
          console.log('less than 0');
          break;
      case num >= 0 && num <= 10:
          console.log('between 0 and 10');
          break;
      case num > 10 && num <= 20:
          console.log('between 10 and 20');
          break;
      default:
          console.log('more than 20');
  }
  