How to override constructor of prototype/intercept object creation in JavaScript?
javascript
Ethan JacksonI would like to intercept all instance creations of EventSource. I tried the following code:
EventSource.prototype.constructor = function(url, config) {
EventSource(url, config);
console.log("intercepted");
}
to override the constructor. It does not work. But the following does work:
EventSource.prototype.sayHi = () => alert("Hi");
new EventSource("my-data").sayHi()
How can I achieve something similar for the constructor/in general instance creation?
I tried searching on the internet and the above code.
Answer
You could override the class itself:
class MyEventSource extends EventSource{
constructor(...args){
super(...args);
console.log('EventSource created');
}
}
window.EventSource = MyEventSource;
new EventSource("my-data")