text: 
  //函数参数默认值
  function show(name, addr="shenzhen") {
      console.log(name, addr)
  }
  
  show("yqq");
  show("Tom");
  show("Tom", "Beijing");
  
  
  //lambda函数
  
  
  var function1 = (age) => {
      console.info(age);
  };
  function1(13);
  