javascript - 回到像 Vue.js vuex 上的 Undo Redo 这样的状态

Question

如何使用 Vuex 进行撤消/重做？我正在开发一个非常复杂的应用程序，Vue 开发工具帮助我在状态之间切换了很多，所以我希望我的应用程序具有该功能。我怎样才能做到这一点？

Answer 1

我已经按如下方式实现了撤消重做:

1) 为vuex创建一个插件

const undoRedoPlugin = (store) => {
  // initialize and save the starting stage
  undoRedoHistory.init(store);
  let firstState = cloneDeep(store.state);
  undoRedoHistory.addState(firstState);

  store.subscribe((mutation, state) => {
    // is called AFTER every mutation
    undoRedoHistory.addState(cloneDeep(state));
  });
}

2) 使用那个插件

new Vuex.Store({
... 
  plugins: [undoRedoPlugin]
});

3) 在undoRedoHistory中保存一个状态的历史

class UndoRedoHistory {
  store;
  history = [];
  currentIndex = -1;

  init(store) {
    this.store = store;
  }

  addState(state) {
    // may be we have to remove redo steps
    if (this.currentIndex + 1 < this.history.length) {
      this.history.splice(this.currentIndex + 1);
    }
    this.history.push(state);
    this.currentIndex++;
  }

  undo() {
    const prevState = this.history[this.currentIndex - 1];
    // take a copy of the history state
    // because it would be changed during store mutations
    // what would corrupt the undo-redo-history
    // (same on redo)
    this.store.replaceState(cloneDeep(prevState));
    this.currentIndex--;
  }

  redo() {
    const nextState = this.history[this.currentIndex + 1];
    this.store.replaceState(cloneDeep(nextState));
    this.currentIndex++;
  }
}

const undoRedoHistory = new UndoRedoHistory();

4)使用它

undoRedoHistory.undo();
...
undoRedoHistory.redo();

如果您的州规模不大，那么克隆该州是一个不错的方法。