Synchronising a property on `window` and an Alpine.js property

alpine-window-sync.html

<div x-data="{
  count: 4,
  init() {
    const self = this
    Object.defineProperty(window, 'count', {
      enumerable: true,
      configurable: true,
      get: function() {
        return self.count
      },
      set: function(val) {
        self.count = val
      }
    });
  }
}" x-text="count"></div>