我最终下载了您的代码并实现了您想要的启动/停止/重置功能。我认为这可能是解释事物的最佳方式 - 展示可以与一些 cmets 一起运行和测试的代码。
我实际上最终得到了两个实现。我将它们称为实施 A 和实施 B。
我认为展示这两种实现会很有趣。希望它不会引起太多混乱。
为了记录，实施 A 是更好的版本。
以下是两种实现的简要说明：
实施 A
此版本在 App 组件级别跟踪状态。通过将props 传递给 Timer 组件来管理计时器。不过，计时器组件确实会跟踪它自己的剩余时间状态。
实施 B
此版本使用 TimerStore 和 TimerAction 模块在 Timer 组件级别跟踪计时器状态，以管理组件的状态和事件。
实现 B 的最大（也可能是致命的）缺点是您只能拥有一个 Timer 组件。这是因为 TimerStore 和 TimerAction 模块本质上是单例。
|
|
实施 A
|
|
此版本在 App 组件级别跟踪状态。这里的大部分cmet都在这个版本的代码中。
通过将props 传递给定时器来管理定时器。
此实现的代码更改列表：
- app-constants.js
- app-actions.js
- app-store.js
- App.jsx
- Timer.jsx
app-constants.js
这里我只是添加了一个用于重置计时器的常量。
module.exports = {
START_TIMER: 'START_TIMER',
STOP_TIMER: 'STOP_TIMER',
RESET_TIMER: 'RESET_TIMER',
CHANGE_PATTERN: 'CHANGE_PATTERN'
};
app-actions.js
我刚刚添加了一个调度方法来处理重置计时器操作。
var AppConstants = require('../constants/app-constants.js');
var AppDispatcher = require('../dispatchers/app-dispatcher.js');
var AppActions = {
changePattern: function() {
AppDispatcher.handleViewAction({
actionType: AppConstants.CHANGE_PATTERN
})
},
resetTimer: function() {
AppDispatcher.handleViewAction({
actionType: AppConstants.RESET_TIMER
})
},
startTimer: function() {
AppDispatcher.handleViewAction({
actionType: AppConstants.START_TIMER
})
},
stopTimer: function() {
AppDispatcher.handleViewAction({
actionType: AppConstants.STOP_TIMER
})
}
};
module.exports = AppActions;
app-store.js
这就是事情发生了一些变化的地方。我在我进行更改的地方添加了详细的内联 cmets。
var AppDispatcher = require('../dispatchers/app-dispatcher.js');
var AppConstants = require('../constants/app-constants.js');
var EventEmitter = require('events').EventEmitter;
var merge = require('react/lib/Object.assign');
// I added a TimerStatus model (probably could go in its own file)
// to manage whether the timer is "start/stop/reset".
//
// The reason for this is that reset state was tricky to handle since the Timer
// component no longer has access to the "AppStore". I'll explain the reasoning for
// that later.
//
// To solve that problem, I added a `reset` method to ensure the state
// didn't continuously loop "reset". This is probably not very "Flux".
//
// Maybe a more "Flux" alternative is to use a separate TimerStore and
// TimerAction?
//
// You definitely don't want to put them in AppStore and AppAction
// to make your timer component more reusable.
//
var TimerStatus = function(status) {
this.status = status;
};
TimerStatus.prototype.isStart = function() {
return this.status === 'start';
};
TimerStatus.prototype.isStop = function() {
return this.status === 'stop';
};
TimerStatus.prototype.isReset = function() {
return this.status === 'reset';
};
TimerStatus.prototype.reset = function() {
if (this.isReset()) {
this.status = 'start';
}
};
var CHANGE_EVENT = "change";
var shapes = ['C', 'A', 'G', 'E', 'D'];
var rootNotes = ['A', 'A#', 'B', 'C', 'C#', 'D', 'D#', 'E', 'F', 'F#', 'G', 'G#'];
var boxShapes = require('../data/boxShapes.json');
// Added a variable to keep track of timer state. Note that this state is
// managed by the *App Component*.
var _timerStatus = new TimerStatus('start');
var _pattern = _setPattern();
function _setPattern() {
var rootNote = _getRootNote();
var shape = _getShape();
var boxShape = _getBoxForShape(shape);
_pattern = {
rootNote: rootNote,
shape: shape,
boxShape: boxShape
};
return _pattern;
}
function _getRootNote() {
return rootNotes[Math.floor(Math.random() * rootNotes.length)];
}
function _getShape() {
return shapes[Math.floor(Math.random() * shapes.length)];
}
function _getBoxForShape(shape) {
return boxShapes[shape];
}
// Simple function that creates a new instance of TimerStatus set to "reset"
function _resetTimer() {
_timerStatus = new TimerStatus('reset');
}
// Simple function that creates a new instance of TimerStatus set to "stop"
function _stopTimer() {
_timerStatus = new TimerStatus('stop');
}
// Simple function that creates a new instance of TimerStatus set to "start"
function _startTimer() {
_timerStatus = new TimerStatus('start');
}
var AppStore = merge(EventEmitter.prototype, {
emitChange: function() {
this.emit(CHANGE_EVENT);
},
addChangeListener: function(callback) {
this.on(CHANGE_EVENT, callback);
},
removeChangeListener: function(callback) {
this.removeListener(CHANGE_EVENT, callback);
},
// Added this function to get timer status from App Store
getTimerStatus: function() {
return _timerStatus;
},
getPattern: function() {
return _pattern;
},
dispatcherIndex: AppDispatcher.register(function(payload) {
var action = payload.action;
switch(action.actionType) {
case AppConstants.RESET_TIMER:
// Handle reset action
_resetTimer();
break;
case AppConstants.START_TIMER:
// Handle start action
_startTimer();
break;
case AppConstants.STOP_TIMER:
// Handle stop action
_stopTimer();
break;
case AppConstants.CHANGE_PATTERN:
_setPattern();
break;
}
AppStore.emitChange();
return true;
})
});
module.exports = AppStore;
App.jsx
App.jsx 中有很多变化，特别是我们将状态从计时器组件移到了 App 组件。代码中再次详述 cmets。
var React = require('react');
var Headline = require('./components/Headline.jsx');
var Scale = require('./components/Scale.jsx');
var RootNote = require('./components/RootNote.jsx');
var Shape = require('./components/Shape.jsx');
var Timer = require('./components/Timer.jsx');
// Removed AppActions and AppStore from Timer component and moved
// to App component. This is done to to make the Timer component more
// reusable.
var AppActions = require('./actions/app-actions.js');
var AppStore = require('./stores/app-store.js');
// Use the AppStore to get the timerStatus state
function getAppState() {
return {
timerStatus: AppStore.getTimerStatus()
}
}
var App = React.createClass({
getInitialState: function() {
return getAppState();
},
// Listen for change events in AppStore
componentDidMount: function() {
AppStore.addChangeListener(this.handleChange);
},
// Stop listening for change events in AppStore
componentWillUnmount: function() {
AppStore.removeChangeListener(this.handleChange);
},
// Timer component has status, defaultTimeout attributes.
// Timer component has an onTimeout event (used for changing pattern)
// Add three basic buttons for Start/Stop/Reset
render: function() {
return (
<div>
<header>
<Headline />
<Scale />
</header>
<section>
<RootNote />
<Shape />
<Timer status={this.state.timerStatus} defaultTimeout="15" onTimeout={this.handleTimeout} />
<button onClick={this.handleClickStart}>Start</button>
<button onClick={this.handleClickStop}>Stop</button>
<button onClick={this.handleClickReset}>Reset</button>
</section>
</div>
);
},
// Handle change event from AppStore
handleChange: function() {
this.setState(getAppState());
},
// Handle timeout event from Timer component
// This is the signal to change the pattern.
handleTimeout: function() {
AppActions.changePattern();
},
// Dispatch respective start/stop/reset actions
handleClickStart: function() {
AppActions.startTimer();
},
handleClickStop: function() {
AppActions.stopTimer();
},
handleClickReset: function() {
AppActions.resetTimer();
}
});
module.exports = App;
Timer.jsx
Timer 也有许多变化，因为我删除了 AppStore 和 AppActions 依赖项以使 Timer 组件更可重用。详细的cmets在代码中。
var React = require('react');
// Add a default timeout if defaultTimeout attribute is not specified.
var DEFAULT_TIMEOUT = 60;
var Timer = React.createClass({
// Normally, shouldn't use props to set state, however it is OK when we
// are not trying to synchronize state/props. Here we just want to provide an option to specify
// a default timeout.
//
// See http://facebook.github.io/react/tips/props-in-getInitialState-as-anti-pattern.html)
getInitialState: function() {
this.defaultTimeout = this.props.defaultTimeout || DEFAULT_TIMEOUT;
return {
timeLeft: this.defaultTimeout
};
},
// Changed this to `clearTimeout` instead of `clearInterval` since I used `setTimeout`
// in my implementation
componentWillUnmount: function() {
clearTimeout(this.interval);
},
// If component updates (should occur when setState triggered on Timer component
// and when App component is updated/re-rendered)
//
// When the App component updates we handle two cases:
// - Timer start status when Timer is stopped
// - Timer reset status. In this case, we execute the reset method of the TimerStatus
// object to set the internal status to "start". This is to avoid an infinite loop
// on the reset case in componentDidUpdate. Kind of a hack...
componentDidUpdate: function() {
if (this.props.status.isStart() && this.interval === undefined) {
this._tick();
} else if (this.props.status.isReset()) {
this.props.status.reset();
this.setState({timeLeft: this.defaultTimeout});
}
},
// On mount start ticking
componentDidMount: function() {
this._tick();
},
// Tick event uses setTimeout. I find it easier to manage than setInterval.
// We just keep calling setTimeout over and over unless the timer status is
// "stop".
//
// Note that the Timer states is handled here without a store. You could probably
// say this against the rules of "Flux". But for this component, it just seems unnecessary
// to create separate TimerStore and TimerAction modules.
_tick: function() {
var self = this;
this.interval = setTimeout(function() {
if (self.props.status.isStop()) {
self.interval = undefined;
return;
}
self.setState({timeLeft: self.state.timeLeft - 1});
if (self.state.timeLeft <= 0) {
self.setState({timeLeft: self.defaultTimeout});
self.handleTimeout();
}
self._tick();
}, 1000);
},
// If timeout event handler passed to Timer component,
// then trigger callback.
handleTimeout: function() {
if (this.props.onTimeout) {
this.props.onTimeout();
}
}
render: function() {
return (
<small className="timer">
({ this.state.timeLeft })
</small>
)
},
});
module.exports = Timer;
|
|
实施 B
|
|
代码更改列表：
- app-constants.js
- timer-actions.js （新）
- timer-store.js （新）
- app-store.js
- App.jsx
- Timer.jsx
app-constants.js
这些可能应该放在一个名为 timer-constants.js 的文件中，因为它们处理 Timer 组件。
module.exports = {
START_TIMER: 'START_TIMER',
STOP_TIMER: 'STOP_TIMER',
RESET_TIMER: 'RESET_TIMER',
TIMEOUT: 'TIMEOUT',
TICK: 'TICK'
};
timer-actions.js
这个模块是不言自明的。我添加了三个事件——超时、滴答和重置。详情见代码。
var AppConstants = require('../constants/app-constants.js');
var AppDispatcher = require('../dispatchers/app-dispatcher.js');
module.exports = {
// This event signals when the timer expires.
// We can use this to change the pattern.
timeout: function() {
AppDispatcher.handleViewAction({
actionType: AppConstants.TIMEOUT
})
},
// This event decrements the time left
tick: function() {
AppDispatcher.handleViewAction({
actionType: AppConstants.TICK
})
},
// This event sets the timer state to "start"
start: function() {
AppDispatcher.handleViewAction({
actionType: AppConstants.START_TIMER
})
},
// This event sets the timer state to "stop"
stop: function() {
AppDispatcher.handleViewAction({
actionType: AppConstants.STOP_TIMER
})
},
// This event resets the time left and sets the state to "start"
reset: function() {
AppDispatcher.handleViewAction({
actionType: AppConstants.RESET_TIMER
})
},
};
timer-store.js
我从AppStore 中分离出计时器的东西。这是为了让 Timer 组件更具可重用性。
Timer 存储跟踪以下状态：
-
计时器状态 - 可以是“开始”或“停止”
-
剩余时间 - 计时器剩余时间
Timer 存储处理以下事件：
- 定时器启动事件将定时器状态设置为启动。
- 定时器停止事件将定时器状态设置为停止。
- tick 事件将剩余时间减 1
- 定时器重置事件将剩余时间设置为默认值并将定时器状态设置为启动
代码如下：
var AppDispatcher = require('../dispatchers/app-dispatcher.js');
var AppConstants = require('../constants/app-constants.js');
var EventEmitter = require('events').EventEmitter;
var merge = require('react/lib/Object.assign');
var CHANGE_EVENT = "change";
var TIMEOUT_SECONDS = 15;
var _timerStatus = 'start';
var _timeLeft = TIMEOUT_SECONDS;
function _resetTimer() {
_timerStatus = 'start';
_timeLeft = TIMEOUT_SECONDS;
}
function _stopTimer() {
_timerStatus = 'stop';
}
function _startTimer() {
_timerStatus = 'start';
}
function _decrementTimer() {
_timeLeft -= 1;
}
var TimerStore = merge(EventEmitter.prototype, {
emitChange: function() {
this.emit(CHANGE_EVENT);
},
addChangeListener: function(callback) {
this.on(CHANGE_EVENT, callback);
},
removeChangeListener: function(callback) {
this.removeListener(CHANGE_EVENT, callback);
},
getTimeLeft: function() {
return _timeLeft;
},
getStatus: function() {
return _timerStatus;
},
dispatcherIndex: AppDispatcher.register(function(payload) {
var action = payload.action;
switch(action.actionType) {
case AppConstants.START_TIMER:
_startTimer();
break;
case AppConstants.STOP_TIMER:
_stopTimer();
break;
case AppConstants.RESET_TIMER:
_resetTimer();
break;
case AppConstants.TIMEOUT:
_resetTimer();
break;
case AppConstants.TICK:
_decrementTimer();
break;
}
TimerStore.emitChange();
return true;
})
});
module.exports = TimerStore;
app-store.js
这可以命名为pattern-store.js，尽管您需要对其进行一些更改才能使其可重用。具体来说，我正在直接监听 Timer 的 TIMEOUT 动作/事件以触发模式更改。如果您想重用模式更改，您可能不希望这种依赖关系。例如，如果您想通过单击按钮或其他方式来更改模式。
除此之外，我刚刚从AppStore 中删除了所有与计时器相关的功能。
var AppDispatcher = require('../dispatchers/app-dispatcher.js');
var AppConstants = require('../constants/app-constants.js');
var EventEmitter = require('events').EventEmitter;
var merge = require('react/lib/Object.assign');
var CHANGE_EVENT = "change";
var shapes = ['C', 'A', 'G', 'E', 'D'];
var rootNotes = ['A', 'A#', 'B', 'C', 'C#', 'D', 'D#', 'E', 'F', 'F#', 'G', 'G#'];
var boxShapes = require('../data/boxShapes.json');
var _pattern = _setPattern();
function _setPattern() {
var rootNote = _getRootNote();
var shape = _getShape();
var boxShape = _getBoxForShape(shape);
_pattern = {
rootNote: rootNote,
shape: shape,
boxShape: boxShape
};
return _pattern;
}
function _getRootNote() {
return rootNotes[Math.floor(Math.random() * rootNotes.length)];
}
function _getShape() {
return shapes[Math.floor(Math.random() * shapes.length)];
}
function _getBoxForShape(shape) {
return boxShapes[shape];
}
var AppStore = merge(EventEmitter.prototype, {
emitChange: function() {
this.emit(CHANGE_EVENT);
},
addChangeListener: function(callback) {
this.on(CHANGE_EVENT, callback);
},
removeChangeListener: function(callback) {
this.removeListener(CHANGE_EVENT, callback);
},
getPattern: function() {
return _pattern;
},
dispatcherIndex: AppDispatcher.register(function(payload) {
var action = payload.action;
switch(action.actionType) {
case AppConstants.TIMEOUT:
_setPattern();
break;
}
AppStore.emitChange();
return true;
})
});
module.exports = AppStore;
App.jsx
在这里，我只是添加了一些用于启动/停止/重置的按钮。单击时，将调度 TimerAction。所以如果你点击了“停止”按钮，我们就会调用TimerAction.stop()
var React = require('react');
var Headline = require('./components/Headline.jsx');
var Scale = require('./components/Scale.jsx');
var RootNote = require('./components/RootNote.jsx');
var Shape = require('./components/Shape.jsx');
var Timer = require('./components/Timer.jsx');
var TimerActions = require('./actions/timer-actions.js');
var App = React.createClass({
render: function() {
return (
<div>
<header>
<Headline />
<Scale />
</header>
<section>
<RootNote />
<Shape />
<Timer />
<button onClick={this.handleClickStart}>Start</button>
<button onClick={this.handleClickStop}>Stop</button>
<button onClick={this.handleClickReset}>Reset</button>
</section>
</div>
);
},
handleClickStart: function() {
TimerActions.start();
},
handleClickStop: function() {
TimerActions.stop();
},
handleClickReset: function() {
TimerActions.reset();
}
});
module.exports = App;
Timer.jsx
其中一个主要变化是我们使用了 TimerAction 和 TimerStore，而不是最初使用的 AppAction 和 AppStore。原因是尝试让 Timer 组件更具可重用性。
定时器有以下状态：
-
状态 计时器状态可以是“开始”或“停止”
-
timeLeft 计时器剩余时间
请注意，我使用了setTimeout 而不是setInterval。我发现setTimeout 更易于管理。
大部分逻辑在_tick 方法中。基本上，只要状态为“开始”，我们就会一直调用setTimeout。
当计时器达到零时，我们会发出timeout 事件的信号。 TimerStore 和 AppStore 正在侦听此事件。
- TimerStore 只会重置计时器。与重置事件相同。
- AppStore 将改变模式。
如果计时器没有达到零，我们会通过发出“tick”事件信号来减去一秒。
最后，我们需要处理定时器停止然后再启动的情况。这可以通过componentDidUpdate 钩子来处理。当组件的状态改变或父组件被重新渲染时，这个钩子会被调用。
在componentDidUpdate 方法中，我们确保仅当状态为“开始”且未定义超时标识符时才开始“滴答”。我们不希望运行多个 setTimeouts。
var React = require('react');
var TimerActions = require('../actions/timer-actions.js');
var TimerStore = require('../stores/timer-store.js');
function getTimerState() {
return {
status: TimerStore.getStatus(),
timeLeft: TimerStore.getTimeLeft()
}
}
var Timer = React.createClass({
_tick: function() {
var self = this;
this.interval = setTimeout(function() {
if (self.state.status === 'stop') {
self.interval = undefined;
return;
}
if (self.state.timeLeft <= 0) {
TimerActions.timeout();
} else {
TimerActions.tick();
}
self._tick();
}, 1000);
},
getInitialState: function() {
return getTimerState();
},
componentDidMount: function() {
TimerStore.addChangeListener(this.handleChange);
this._tick();
},
componentWillUnmount: function() {
clearTimeout(this.interval);
TimerStore.removeChangeListener(this.handleChange);
},
handleChange: function() {
this.setState(getTimerState());
},
componentDidUpdate: function() {
if (this.state.status === 'start' && this.interval === undefined) {
this._tick();
}
},
render: function() {
return (
<small className="timer">
({ this.state.timeLeft })
</small>
)
}
});
module.exports = Timer;