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如何检测一个数组被另一个相同的数组替换?

debugging arrays javascript

slartidan · 技术社区 · 6 年前

window.myarray = []
console.log(window.myarray); // outputs: []

window.myarray.push("bla"); // an irrelevant manipulation
console.log(window.myarray); // outputs: ["bla"]

window.myarray = ["bla"]; // a change of the array's identity!
console.log(window.myarray); // still outputs: ["bla"]

即使新旧数组的内容相同,如何检测存储在变量中的数组是否已更改?

2 回复 | 直到 6 年前

ChrisG 6 年前

window.myarray = []
var backup = window.myarray;

window.myarray.push("bla"); // an irrelevant manipulation
console.log(backup === window.myarray); // true

window.myarray = ["bla"]; // a change of the array's identity!
console.log(backup === window.myarray); // false

请注意 backup

mpm 6 年前

你可以用代理

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy

(function() {
  let _myArray;
  Object.defineProperty(window, "myArray", {
    set(value) {
      _myArray = value;
      console.log('changed', value);
    },
    get() {
      return _myArray
    }
  })
}())

window.myArray = [];

window.myArray = ['bar'];

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/defineProperty