How to utlize `cb`?

[bilogic]

tailwindcss-stimulus-components/src/dropdown.js

Lines 99 to 112 in 11f7338

 _hide(cb) { 
   setTimeout( 
     (() => { 
       if (this.hasButtonTarget) { 
         this.buttonTarget.setAttribute("aria-expanded", "false") 
       } 
       this._invisibleClassList[0].forEach(klass => this.menuTarget.classList.add(klass)) 
       this._visibleClassList[0].forEach(klass => this.menuTarget.classList.remove(klass)) 
       this._activeClassList[0].forEach(klass => this.activeTarget.classList.remove(klass)) 
       this._leavingClassList[0].forEach(klass => this.menuTarget.classList.add(klass)) 
       setTimeout( 
         (() => { 
           this._leavingClassList[0].forEach(klass => this.menuTarget.classList.remove(klass)) 
           if (typeof cb == 'function') cb() 

I noticed this cb in the controllers, does it mean there is a way to pass a callback into the controllers?
My use case is, I would like to have a toggle switch to change some setting on the server, but I don't want to be hardcoding the XHR/AJAX inside the controller itself.

Any examples of how I can do this callback from controller back to the HTML side?

Thank you.

UPDATE: ok, I misunderstood the code