Синтаксис for…in

function WithVar(items) { 
  var prostoPermennaja1 = 123; 
  for (var item1 in items) { 
    //console.log(item1); 
  } 
} 
 
function WithoutVar(items) { 
  prostoPermennaja2 = 123; 
  for (item2 in items) { 
    //console.log(item2); 
  } 
} 
 
var items = {a:1, b:2}; 
 
WithVar(items); 
console.log(window.item1); 
console.log(window.prostoPermennaja1); 
 
WithoutVar(items); 
console.log(window.item2); 
console.log(window.prostoPermennaja2);

let obj = { 
'qwe': 1, 
'asd': 2 
} 
for (i in obj) { 
  console.log(obj[i]); 
}

'use strict' 
let obj = { 
'qwe': 1, 
'asd': 2 
} 
for (i in obj) { 
  console.log(obj[i]); 
}