/**
 * When you have two-way bindings, but the actual bound value will not equal
 * the value you initially passed in, then to avoid an infinite loop you
 * need to increment a counter every time you pass in a value, decrement the
 * same counter every time the bound value changed, but only bubble up
 * the event when the counter is zero.
 *
Example:

Let's say DrawingRecognitionCanvas is a deep-learning backed canvas
that, when given the name of an object (e.g. 'dog'), draws a dog.
But whenever the drawing on it changes, it also sends back its interpretation
of the image by way of the @newObjectRecognized event.

<input
  type="text"
  placeholder="an object, e.g. Dog, Cat, Frog"
  v-model="identifiedObject" />
<DrawingRecognitionCanvas
  :object="identifiedObject"
  @newObjectRecognized="identifiedObject = $event"
  />

new TwoWayBindingWrapper((increment, decrement, shouldUpdate) => {
  this.$watch('identifiedObject', () => {
    // new object passed in
    increment()
  })
  this.$deepLearningBackend.on('drawingChanged', () => {
    recognizeObject(this.$deepLearningBackend)
      .then((object) => {
        decrement()
        if (shouldUpdate()) {
          this.$emit('newObjectRecognized', object.name)
        }
      })
  })
})
 */
export default function TwoWayBindingWrapper(fn) {
  let counter = 0

  fn(
    () => {
      counter += 1
    },
    () => {
      counter = Math.max(0, counter - 1)
    },
    () => counter === 0
  )
}