javascript - "this"在另一个对象的数组内访问 's "this"- javascript

Question

这个问题已经有答案了:

How do I correctly clone a JavaScript object? (81 个回答)

已关闭 5 年前。

考虑这个例子:

如果你要运行上面的代码，控制台消息将是100。为什么当我将100添加到obj2的“this”中的位置时，它打印出100？如何使 obj2 拥有自己独特的“this”？另请注意，这是我的代码的简化示例，我不能只在 obj2 中创建一个包含所有内容的单独对象。

var obj1 = function() {
  this.obj2Arr = [];
  this.pos = {
    "x": 0,
    "y": 0
  };
  this.obj2Arr.push(new obj2(this.pos));
  console.log(this.pos.x);
  // Prints out 100 even though obj2 was where I added the 100 for it's "this".
  // Why does it do that, and how do I make obj2's "this" unique to it?
};

var obj2 = function(pos) {
  this.pos = pos;
  this.pos.x = this.pos.x + 100;
};

var example = new obj1();
console.log(example);

Answer 1

这是因为 pos 是一个对象，并且对象在 JavaScript 中始终通过引用传递。

要回答您的问题:使用Object.assign 创建一个新对象:

var obj1 = function() {
  this.obj2Arr = [];
  this.pos = {
    "x": 0,
    "y": 0
  };
  this.obj2Arr.push(new obj2(Object.assign({}, this.pos)));
  console.log(this.pos.x);
};

var obj2 = function(pos) {
  this.pos = pos;
  this.pos.x = this.pos.x + 100;
};

var example = new obj1();
console.log(example);