js块级作用域问题，不明白为什么第二个打印是2020，希望有大佬不吝赐教

Question

  var a = 1999;
  {
    console.log(a); // function a(){}
    a = 2020;
    function a() {}
    a = 2021;
  }
  console.log(a); // 2020  
  
  

Answer 1

https://blog.csdn.net/qq_4504...