【发布时间】:2020-01-26 22:45:08
【问题描述】:
我有一个简单的 React & Redux 应用程序,但我遇到了奇怪的问题。 这里是我项目的主要文件:
Home.js 文件:
import React, { Component } from "react";
import { bindActionCreators } from "redux";
import * as productActions from "../../actions/product";
import { connect } from "react-redux";
class Home extends Component {
componentWillMount() {
this.props.actions.getProducts();
}
render() {
const { products, actions } = this.props;
const cart = products.filter(product => product.addToCart);
return (
<div className="home mt-5">
<div className="row">
<div className="col-12">
<h2 className="mb-3">Products</h2>
</div>
</div>
<div className="row mt-3">
{products.map(product => (
<div key={product.id} className="col-sm-6 col-md-3">
<div
className="view_details"
onClick={() => actions.addToCart(product)}
>
{product.name}{" "}
<u>{product.addToCart ? "Remove" : "Add to Cart"}</u>
</div>
</div>
))}
</div>
<div className="row mt-4">
<div className="col-12">
<h2 className="mb-3">Cart:</h2>
{cart.map(product => (
<div key={product.id}>{product.name}</div>
))}
</div>
</div>
</div>
);
}
}
export default connect(
state => ({
products: state.product.products
}),
dispatch => ({
actions: bindActionCreators(productActions, dispatch)
})
)(Home);
actions/product.js 文件:
import { FETCH_PRODUCTS_DATA, ADD_TO_CART } from "../types/products";
export const getProducts = () => dispatch =>
fetch(`data.json`)
.then(response => response.json())
.then(response => {
dispatch({
type: FETCH_PRODUCTS_DATA,
payload: response.products
});
});
export const addToCart = product => ({
type: ADD_TO_CART,
product
});
reducers/productReducer.js 文件:
import { FETCH_PRODUCTS_DATA, ADD_TO_CART } from "../types/products";
const initialState = {
products: []
};
export default function(state = initialState, action) {
switch (action.type) {
case FETCH_PRODUCTS_DATA:
return {
...state,
products: action.payload.map(product => ({
...product,
addToCart: false
}))
};
case ADD_TO_CART:
return {
...state,
products: state.products.map(product =>
product.id === action.product.id
? { ...product, addToCart: !product.addToCart }
: product
)
};
default:
return state;
}
}
这里还有更多不需要与您分享的文件。 上面的代码一切都按预期工作,问题是当我不使用 bindActionCreators 方法时。 使用以下 Home.js 文件(带有 mapStateToProps 和 mapDispatchToProps),只有 getProducts 操作运行良好,但 addToCart 操作给我以下错误:“无法读取未定义的属性 'id'”:reducers/productReducer.js: 20
带有 mapStateToProps 和 mapDispatchToProps 的 Home.js 文件:
import React, { Component } from "react";
import { getProducts, addToCart } from "../../actions/product";
import { connect } from "react-redux";
class Home extends Component {
componentWillMount() {
this.props.actions.getProducts();
}
render() {
const { products, actions } = this.props;
const cart = products.filter(product => product.addToCart);
return (
<div className="home mt-5">
<div className="row">
<div className="col-12">
<h2 className="mb-3">Products</h2>
</div>
</div>
<div className="row mt-3">
{products.map(product => (
<div key={product.id} className="col-sm-6 col-md-3">
<div
className="view_details"
onClick={() => actions.addToCart(product)}
>
{product.name}{" "}
<u>{product.addToCart ? "Remove" : "Add to Cart"}</u>
</div>
</div>
))}
</div>
<div className="row mt-4">
<div className="col-12">
<h2 className="mb-3">Cart:</h2>
{cart.map(product => (
<div key={product.id}>{product.name}</div>
))}
</div>
</div>
</div>
);
}
}
const mapStateToProps = state => {
return {
products: state.product.products
};
};
const mapDispatchToProps = dispatch => {
return {
actions: {
getProducts: () => dispatch(getProducts()),
addToCart: () => dispatch(addToCart())
}
};
};
export default connect(mapStateToProps, mapDispatchToProps)(Home);
谁能告诉我为什么?
谢谢!
【问题讨论】: