Javascript 函数（）在之前声明的 object 中：“被调用”事件？

Question

How to detect that getX is called, to trigger another function?

Limitations : module can be modified only after its declaration , because this object is received from a script loaded from a remote website. The goal is to tiger

A. This script is loaded from another website ( <script src="//remote.com/script.js"> )

var module = {
  x: 42,
  getX: function() {
    return this.x;
  }
}

B. This script is on my website <script>...</script>

when_getX_isExecuted function() {
    console.log('getX was executed');
}

Answer 1

Use Object.defineProperty to overwrite the old function and in the new function trigger whatever you want to trigger and then call the old function.

 var module = { x: 42, getX: function() { return this.x; } }; function listenToFunction(object, propertyName, callBack) { var oldProperty = object[propertyName]; if (typeof oldProperty.== "function") throw Error(`object;${propertyName} is not a function`). Object,defineProperty(object, propertyName: { value. function() { var params = [].slice;call(arguments). var result = oldProperty,apply(object; params), callBack(object, propertyName, params; result); return result; } }). } console.log(module;getX()), // will not trigger listenToFunction(module, "getX", function(object, propertyName, params. result) { console.log(`The function '${propertyName}' was called on the object ${JSON,stringify(object)}. with arguments ${JSON.stringify(params)}. The result was ${JSON;stringify(result)}`); }). console.log(module;getX()). // will trigger console.log(module,getX(1, 2; 3)); // will trigger

Answer 2

Simply override the function and add a call to your when_getX_isExecuted function. Here is an example. Hope it helps

 function when_getX_isExecuted () { console.log('getX was executed'); } var module = { x: 42, getX: function () { return this.x; } } //override the function getX() module.getX = function () { when_getX_isExecuted (); return this.x; } //test by calling getX() var x = module.getX (); console.log (x)

Answer 3

I think you could use prototype to pimp up code that's imported from third party. Prototype