合并/合并两个javascript对象，而不会失去顺序

Question

我正在尝试使用纯JavaScript代码从2个小对象中创建一个大型js对象。

这是我尝试过的一个例子。

var obj1 = {
  1: {title:'T1'},
  4: {title:'T2'},
  3: {title:'T3'},
};

var obj2 = {
  5: {title:'T1'},
  2: {title:'T2'},
  6: {title:'T3'},
};
var obj3 = Object.assign(obj1,obj2);

我上面获得的输出是这个

{
  1: {title:'T1'},
  2: {title:'T2'},
  3: {title:'T3'},
  4: {title:'T2'},
  5: {title:'T1'},
  6: {title:'T3'},
};

这就是我希望得到的答复。

{
  1: {title:'T1'},
  4: {title:'T2'},
  3: {title:'T3'},
  5: {title:'T1'},
  2: {title:'T2'},
  6: {title:'T3'},
};