簡介
通過包裝reducer,創建一個state History,保留歷史state,可以做退一步,進一步操作
1.install
npm install --save redux-undo@beta import ReduxUndo from 'redux-undo';
2.API(包裝reducer,其中config參數為history配置)
import undoable from 'redux-undo'; undoable(reducer) undoable(reducer, config)
2.1 和 combineReducers 配合使用
combineReducers({
counter: undoable(counter)
})
3.History API
3.1 包裝后的renducers 變成了,可通過state.present (獲取當前), state.past (獲取過去)
{
past: [...pastStatesHere...],
present: {...currentStateHere...},
future: [...futureStatesHere...]
}
4.發起撤銷重做 Undo/Redo Actions
store.dispatch(ActionCreators.undo()) // undo the last action 退一步 store.dispatch(ActionCreators.redo()) // redo the last action 進一步 store.dispatch(ActionCreators.jump(-2)) // undo 2 steps store.dispatch(ActionCreators.jump(5)) // redo 5 steps store.dispatch(ActionCreators.jumpToPast(index)) // jump to requested index in the past[] array store.dispatch(ActionCreators.jumpToFuture(index)) // jump to requested index in the future[] array store.dispatch(ActionCreators.clearHistory()) // [beta only] Remove all items from past[] and future[] arrays
5.配置項config
undoable(reducer, { limit: false, // set to a number to turn on a limit for the history // 保存到歷史的數量 filter: () => true, // see `Filtering Actions` section //過濾一部分action,不記錄/記錄在history undoType: ActionTypes.UNDO, // define a custom action type for this undo action redoType: ActionTypes.REDO, // define a custom action type for this redo action jumpType: ActionTypes.JUMP, // define custom action type for this jump action jumpToPastType: ActionTypes.JUMP_TO_PAST, // define custom action type for this jumpToPast action jumpToFutureType: ActionTypes.JUMP_TO_FUTURE, // define custom action type for this jumpToFuture action clearHistoryType: ActionTypes.CLEAR_HISTORY, // [beta only] define custom action type for this clearHistory action initTypes: ['@@redux-undo/INIT'] // history will be (re)set upon init action type debug: false, // set to `true` to turn on debugging neverSkipReducer: false, // prevent undoable from skipping the reducer on undo/redo })
6.初始化,history, (看這個了解到,其實就是把 app 的 state={ todos:[], visiFilter:'showAll' } 包裝一層,變成下面的形式
import { createStore } from 'redux'; const initialHistory = { past: [0, 1, 2, 3], present: 4, future: [5, 6, 7] } const store = createStore(undoable(counter), initialHistory);
1.不初始化歷史,只定義當前
import { createStore } from 'redux'; const store = createStore(undoable(counter), {foo: 'bar'}); // will make the state look like this: { past: [], present: {foo: 'bar'}, future: [] }
7.Filtering Actions (通過config)
7.1 用于過濾,記錄進History的state
7.2 包含include, 排除exclude
import undoable, { includeAction, excludeAction } from 'redux-undo'; undoable(reducer, { filter: includeAction(SOME_ACTION) }) undoable(reducer, { filter: excludeAction(SOME_ACTION) }) // they even support Arrays: undoable(reducer, { filter: includeAction([SOME_ACTION, SOME_OTHER_ACTION]) }) undoable(reducer, { filter: excludeAction([SOME_ACTION, SOME_OTHER_ACTION]) })
7.3 加入更多邏輯過濾 Custom filters
undoable(reducer, { filter: function filterActions(action, currentState, previousHistory) { return action.type === SOME_ACTION; // only add to history if action is SOME_ACTION } }) // The entire `history` state is available to your filter, so you can make // decisions based on past or future states: undoable(reducer, { filter: function filterState(action, currentState, previousHistory) { let { past, present, future } = previousHistory; return future.length === 0; // only add to history if future is empty } })
7.4 合并多個filter函數
import undoable, {combineFilters} from 'redux-undo' function isActionSelfExcluded(action) { return action.wouldLikeToBeInHistory } function areWeRecording(action, state) { return state.recording } undoable(reducer, { filter: combineFilters(isActionSelfExcluded, areWeRecording) })
7.5 忽略指定的action---- Ignoring Actions
import { ignoreActions } from 'redux-ignore' ignoreActions( undoable(reducer), [IGNORED_ACTION, ANOTHER_IGNORED_ACTION] ) // or define your own function: ignoreActions( undoable(reducer), (action) => action.type === SOME_ACTION // only add to history if action is SOME_ACTION )
Note: Since beta4
, only actions resulting in a new state are recorded. This means the (now deprecated) distinctState()
filter is auto-applied.
這句話的意思應該是:從beta4 開始,只有觸發 action 產生的 state 才會記錄在 history, 有redo/undo 產生的是不會被記錄的,可以使用distinctState() 兼容
然而我并不明白istinctState是做什么的,看到,請幫我解惑,在此謝過
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