Function createWatcher

static/vuejs/vue.runtime.esm.js:2852–2862

(vm, key, handler)

}

function createWatcher (vm, key, handler) {
  var options;
  if (isPlainObject(handler)) {
    options = handler;
    handler = handler.handler;
  }
  if (typeof handler === 'string') {
    handler = vm[handler];
  }
  vm.$watch(key, handler, options);
}

function stateMixin (Vue) {
  // flow somehow has problems with directly declared definition object