JavaScript对象镜像/单向属性同步 [英] JavaScript Object Mirroring/One-way Property Syncing

问题描述

出于安全考虑，我需要一个镜像对象。即，如果我创建对象A，并浅层克隆A的副本并将其称为B，则只要A的属性发生更改，我希望B自动更新以反映更改，但不是相反。换句话说，单向属性同步。

For security purposes, I have a need for a "mirrored" object. i.e. if I create object A, and shallow-clone a copy of A and call it B, whenever a property of A changes, I hope to have B automatically update itself to reflect the changes, but not the other way around. In other words, one-way property syncing.

我的问题：我是否已经知道了解决方案？

My question: is there already a solution out in the wild that I'm not aware of?

考虑用observe-js实现一个库（ https://github.com/polymer/observe-js ），但我想在继续之前我应该​​四处询问。谢谢。

Was thinking of implementing a library with observe-js (https://github.com/polymer/observe-js), but thought I should ask around before proceeding. Thanks.

推荐答案

假设您不需要支持IE8及更早版本，您可以使用getter在现代浏览器上执行此操作。

Assuming you don't need to support IE8 and earlier, you can use getters to do that on modern browsers.

function proxy(src) {
  var p = {};
  Object.keys(src).forEach(function(key) {
    Object.defineProperty(p, key, {
      get: function() {
        return src[key];
      }
    });
  });
  return p;
}

var a = {
  foo: "Original foo",
  bar: "Original bar"
};
var b = proxy(a);

console.log(b.foo);    // "Original foo"
a.foo = "Updated foo"; // Note we're writing to a, not b
console.log(b.foo);    // "Updated foo"

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