JavaScript 构造函数监听此变量更改

Question

我正在创建一个 JavaScript 对象，并且希望能够被动地检测传入对象中的更改。

我尝试使用代理对象，但无法重现所需的行为。我尝试在代码中实现的一个示例是:Listening for variable changes in JavaScript

这是我正在使用的构造函数的非常基本的外壳:

function Fluid(options) {
    this.options = options;
    // Here is where I use the options object, and would like to be able to re-evaluate certain pieces of code if any values in 'this.options' changes.
}

let myApp = new Fluid({
    testValue: 1
});

我的预期输出可能是这样的:

function Fluid(options) {
    this.options = options;

    function doThings() {
        if(this.options.testValue === 1) {
            console.log("The value is 1");
        } else {
            console.log("The value is not 1");
        }
    }

    doThings();

    // Here I would implement the code to detect changes in the this.options object, and if this.options changes, I can execute a function, like doThings()

}

let myApp = new Fluid({
   testValue: 1
});

// Console: The value is 1

myApp.testValue = 2;

// Console: The value is not 1

Answer 1

在尝试了更多代理对象之后，我能够使用以下代码解决此问题:

function Fluid(options) {
    this.options = options;

    let proxyHandler = {
        set: (target, objectKey, value) => {
            console.log(`Setting property "${objectKey}" = "${value}"`);
            return target[objectKey] = value;
        }
    };

    this.options = new Proxy(this.options, proxyHandler);

}