/**

• Evaluate the getter, and re-collect dependencies.
  */
  get () {
  pushTarget(this)
  let value
  const vm = this.vm
  try {
  value = this.getter.call(vm, vm)
  } catch (e) {
  if (this.user) {
  handleError(e, vm, getter for watcher "${this.expression}")
  } else {
  throw e
  }
  } finally {
  // “touch” every property so they are all tracked as
  // dependencies for deep watching
  if (this.deep) {
  traverse(value)
  }
  popTarget()
  this.cleanupDeps()
  }
  return value
  }