How to pass callback function to a JS class?

I have created a little class in JS to handle buttons across a site i’m building. When creating a new instance of a Button i want to be able to pass a callback function.

Currently i’m creating the instance like this: (Class code follows below)

import Button from './scripts/button';
const btn = document.getElementById('test');
new Button(btn);

What i want to do is something like this:

    import Button from './scripts/button';
    const btn = document.getElementById('test');
    new Button(btn, function() {
      console.log('im clicked');
    });

The code for the Button class looks like this:

class Button {

  constructor(el) {
    this.element = el;
  }

  /*
    more to come here, but this is to simplify stuff
  */
}

export default Button;

How would i do this?

>Solution :

You’ll need to add the callback to the constructor(), and then call it within the constructor, so it looks like:

constructor(el, cb) {
  this.element = el;
  cb();
}