[1,2,3,2,4,4]

[{a:1},{a:2},{a: 1}]

let getFun = (str) => {
return 'aa'
}
class Bb {
constructor () {
  getFun = (str) => {
    return 'bb'
  }
}
getA = getFun('a')
}
var bb = new Bb()
bb.getA

var a=10;         
function aaa(){             
  console.log(a);
};                    
function bbb(){            
  var a=20;            
  aaa();        
}        
bbb()

function A(){                 
  let a=1;                 
  window.B=function(){                     
      console.log(a)                 
  }            
}            
A();            
B();