code: function observableChanged(change) {
    const store = this;
    action(() => {
      store.dataChanges.set(change.name, change.newValue);
  
      if (store.isSame(store.dataChanges.get(change.name), store.dataServer[change.name])) {
        store.dataChanges.delete(change.name);
      }
    })();
  }
docs: Observes data and if changes come, add them to dataChanges,
  unless it resets back to dataServer value, then clear that change
  @this {FormStore}
  @param {Object} change
  @param {String} change.name - name of property that changed
  @param {*} change.newValue