DVA简介
dva 是基于现有应用架构 (redux + react-router + redux-saga 等)的一层轻量封装，没有引入任何新概念，全部代码不到 100 行。( Inspired by elm and choo. )
dva 是 framework，不是 library，类似 emberjs，会很明确地告诉你每个部件应该怎么写，这对于团队而言，会更可控。另外，除了 react 和 react-dom 是 peerDependencies 以外，dva 封装了所有其他依赖。
DVA一共有5个API
import dva, { connect } from 'dva';
// 1. Create app
const app = dva();
// 2. Add plugins (optionally)
app.use(plugin);
// 3. Register models
app.model(model);
// 4. Connect components and models
const App = connect(mapStateToProps)(Component);
// 5. Config router with Components
app.router(routes);
// 6. Start app
app.start('#root');
API
1. app = dva(opts)
新建一个dva app，你可以配置history和initialState选项。
opts.history: the history for router, default: hashHistory
opts.initialState: initialState of the app, default: {}
import { browserHistory } from 'dva/router';
const app = dva({
history: browserHistory,
});
2. app.use(hooks)
- onError(fn): called when an effect or subscription emit an error
- onAction(array|fn): called when an action is dispatched, used for registering redux middleware, support Arrayfor convenience
- onStateChange(fn): called after a reducer changes the state
- onReducer(fn): used for apply reducer enhancer
- onEffect(fn): used for wrapping effect to add custom behavior, e.g. dva-loading for automatical loading state
- onHmr(fn): used for hot module replacement
- extraReducers(object): used for adding extra reducers, e.g. redux-form needs extra form reducer
3. app.model(obj)
- namespace：model的名称空间
- state：初始state
-
reducers：同步的修改状态的操作，由actions触发
(state, action) => state -
effects：异步的操作，并不直接修改state，由actions触发，也可以调用actions。
(action, { put, call, select }) -
subscriptions：异步的只读操作，并不直接修改state，可以调用actions。
({ dispatch, history })
put(action)和dispatch(action)
这里effects中的put(action)等同于subscriptions中的dispatch(action)，它们的作用都是分发一个action。
yield put({ type: actionType, payload: attachedData, error: errorIfHave});
dispatch({ type: actionType, payload: attachedData, error: errorIfHave});
call(asyncFunction)
调用一个异步函数
const result = yield call(api.fetch, { page: 1 });
select(function)
从全局状态中选择数据
const count = yield select(state => state.count);
4. app.router(({ history }) => routes)
import { Router, Route } from 'dva/routes';
app.router(({ history } => ({
<Router history={ history }>
<Route path="/" component={App} />
</Router>
});
5. app.start(selector?)
启动应用，selector是可选的。如果没有selector参数，它会返回一个函数，这个函数返回JSX元素。
