javascript - 如何引用一个对象而不是复制它？

Question

如何引用一个对象而不是复制它？如下代码所示，显然 o2 在调用 o = 1 时保持不变。如果我想在o改变的时候让o2改变，怎么办？

var o = { 
  a: {
    b:2
  }
}; 
// 2 objects are created. One is referenced by the other as one of its property.
// The other is referenced by virtue of being assigned to the 'o' variable.
// Obviously, none can be garbage-collected


var o2 = o; // the 'o2' variable is the second thing that 
            // has a reference to the object
o = 1;      // now, the object that was originally in 'o' has a unique reference
            // embodied by the 'o2' variable

Answer 1

你可以在闭包的帮助下做到这一点:

function Closure() {
    var o = { 
      a: {
        b:2
      }
    }; 

    this.getO = function () {
        return o;
    };
}

var closure = new Closure(),
    newO = closure.getO();
newO.a = 111;

console.dir(closure.getO());