我正在构建一个基本上模拟电子商务的应用程序原型。我有一些组件,每个组件都有可以添加到购物车的不同项目(下面,我仅显示一个示例,说明其基本工作原理)。使用react-router通过不同的路由访问这些组件。有一个标题组件,显示购物车中当前的物品数量。标头从redux存储中的状态获取购物车中的商品数量。但是,如果我导航到新路线,则商店将恢复为默认状态。当新路线导航到时,我需要商店保持其状态。例如,如果我转到ShoppingPage,将商品添加到购物车,然后返回首页,则我需要购物车中仍然有商品。
actions.js
export const actionTypes = Object.freeze({
UPDATE_CART: Symbol('UPDATE_CART'),
});
export const updateCart = (payload) => {
return {
type: actionTypes.UPDATE_CART,
payload,
};
};
export default actionTypes;
reducer.js
import actions from './actions';
export const INITIAL_STATE = {
cart: [],
};
export default (state = INITIAL_STATE, action) => {
switch (action.type) {
case actions.UPDATE_CART: {
return {
...state,
cart: action.payload,
};
}
default: {
return state;
}
};
};
index.js
import React from 'react';
import ReactDOM from 'react-dom';
import App from './App';
import * as serviceWorker from './serviceWorker';
import { BrowserRouter } from 'react-router-dom';
import { Provider } from 'react-redux';
import { createStore } from 'redux';
import reducer, { INITIAL_STATE } from './reducer';
const store = createStore(reducer, INITIAL_STATE);
console.log(store.getState());
ReactDOM.render(
<Provider store ={store}>
<BrowserRouter>
<App />
</BrowserRouter>
</Provider>
, document.getElementById('root'));
serviceWorker.unregister();
ShoppingPage.js
import React, { Component } from 'react';
import { connect } from 'react-redux';
import { updateCart } from './actions';
class ShoppingPage extends Component {
addToCart = () => {
const cart = [...this.props.cart];
cart.push('new item');
this.props.modifyCart(cart);
render() {
return(
<div>
<button onClick={addToCart}>
Add To Cart
</button>
</div>
)
}
}
const mapDispatchToProps = dispatch => ({
modifyCart: payload => dispatch(updateCart(payload)),
});
const mapStateToProps = state => ({
cart: state.cart,
});
export default connect(
mapStateToProps,
mapDispatchToProps,
)(ShoppingPage);
Home.js
import React, { Component } from 'react';
import { ListGroup, ListGroupItem } from 'reactstrap';
class Home extends Component {
render() {
return(
<div>
<ListGroup>
<ListGroupItem><a href='/ShoppingPage'>ShoppingPage</a></ListGroupItem>
</div>
)
}
}
export default Home;
Header.js
import React, { Component } from 'react';
import { Navbar, NavbarBrand } from 'reactstrap';
import { connect } from 'react-redux';
class Header extends Component {
render() {
return(
<Navbar sticky='top' className='nav'>
<NavbarBrand href='/'>Online Shopping</NavbarBrand>
<span>{'Items in Cart: '}{this.props.cart.length}</span>
</Navbar>
)
}
}
const mapStateToProps = state => ({
cart: state.cart,
});
export default connect(
mapStateToProps
)(Header);
Routes.js
import React from 'react';
import { Switch, Route } from 'react-router-dom';
import Home from './Home';
import ShoppingPage from './ShoppingPage';
const Routes = () => (
<Switch>
<Route exact path='/' component={Home} />
<Route exact path='/ShoppingPage' component={ShoppingPage} />
</Switch>
);
export default Routes;
App.js
import React from 'react';
import Routes from './Routes';
import Header from './Header';
function App() {
return (
<div>
<Header />
<Routes />
</div>
);
}
export default App;
可能发生的情况是,在导航过程中,Web应用程序再次“重新加载”(这将清除Redux状态)。为了使用React Router进行导航,您需要查看<Link>
。
例如,
Home.js
<a href='/ShoppingPage'>ShoppingPage</a>
应该更改为:
<Link to="/ShoppingPage">ShoppingPage</Link>
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