如何检测何时访问JavaScript对象变量？ [英] How to detect when a JavaScript object variable is accessed?

问题描述

我正在尝试调试一些javascript代码，我需要知道何时访问/运行对象上的特定变量。不是在它发生变化时，而是在脚本运行到特定变量时。

I'm trying to debug some javascript code and I need to know when a particular variable on an object is accessed/run. Not when it changes, but when the script runs to a particular variable.

有办法吗？

推荐答案

你可以用 Reflect.apply（）或 Proxy.handler（）

const o = {
  abc: function() {
    return 123
  },
  def: function() {
    return "456"
  }
}

for (let [key, value] of Object.entries(o)) {
  if (typeof value === "function") {
    let fn = o[key];
    Object.assign(o, {
      [key]: function(...args) {
        // do stuff
        console.log(key + " proxy arguments:", args);
        return Reflect.apply(fn, o, args);
      }
    })
  }
}

console.log(o.abc(1, 2, 3), o.def(4, 5, 6));

const o = {
  abc: function() {
    return 123
  },
  def: function() {
    return "456"
  }
}

for (let [key, value] of Object.entries(o)) {
  if (typeof value === "function") {
    Object.assign(o, {
      [key]: new Proxy(o[key], {
        apply: function(o, thisArg, args) {
          // do stuff
          console.log(key + " proxy arguments:", args);
          return args;
        }
      })
    })
  }
}
  
console.log(o.abc(1,2,3), o.def(4,5,6));

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