checked_controller.js

import { Controller } from "stimulus"

export default class extends Controller {
  static targets = ["input"]
    
  connect() {
    this.update()
  }   
        
  update() {
    const checked = this.inputTarget.checked
        
    if (checked) {
      this.element.classList.add("checked-border--checked")
    } else {
      this.element.classList.remove("checked-border--checked")
    }
  }
}