我正在按照一个教程尝试学习Redux。我执行了第一个操作,这是一个简单的GET API调用,但是卡在了我要创建的下一个操作上。该代码如下所示:
在组件中:
class ShoppingList extends Component {
componentDidMount() {
this.props.getItems();
}
handleClick = id => {
console.log("component " + id);
this.props.deleteItem(id);
};
render() {
const { items } = this.props.item;
return (
<Container>
<ListGroup>
<TransitionGroup className="shoppingList">
{items.map(({ id, name }) => (
<CSSTransition key={id} timeout={500} classNames="fade">
<ListGroupItem>
<Button
className="button1"
color="danger"
size="sm"
onClick={e => this.handleClick(id, e)}
>
×
</Button>
{name}
</ListGroupItem>
</CSSTransition>
))}
</TransitionGroup>
</ListGroup>
</Container>
);
}
}
ShoppingList.propTypes = {
getItems: PropTypes.func.isRequired,
item: PropTypes.object.isRequired,
deleteItem: PropTypes.func.isRequired
};
const mapStateToProps = state => ({
item: state.item
});
export default connect(mapStateToProps, { getItems, deleteItem })(ShoppingList);
在我的减速器中:
const initialState = {
items: [
{ id: 3, name: "Eggs" },
{ id: 4, name: "Milk" },
{ id: 5, name: "Steak" },
{ id: 6, name: "Water" }
]
};
export default function(state = initialState, action) {
switch (action.type) {
case GET_ITEMS:
return {
...state
};
case DELETE_ITEM:
console.log("reducer");
return {
...state,
items: state.items.filter(item => item.id !== action.id)
};
default:
return state;
}
}
在我的操作文件中:
export const getItems = () => {
return {
type: GET_ITEMS
};
};
export const deleteItem = id => {
console.log("actions");
return {
type: DELETE_ITEM,
payload: id
};
};
但是,当我单击按钮尝试从列表中删除项目时,什么也没有发生。我可以在Redux控制台中看到正在分派操作,但是它似乎没有任何作用。有什么建议吗?
答案 0 :(得分:1)
您正在进行deleteItem
操作{ type, payload }
。相反,您可以在化简的return语句中使用{ type, id }
或使用payload
。
我将执行以下操作-因此您将id
而不是action
传递给payload
:
export const deleteItem = id => {
console.log("actions");
return {
type: DELETE_ITEM,
id
};
};
或者是以后使用的最佳选择-保持payload
仅将id
添加为属性:
// action
export const deleteItem = id => {
console.log("actions");
return {
type: DELETE_ITEM,
payload: { id }
};
};
// reducer
case DELETE_ITEM:
// here destructuring the property from payload
const { id } = action.payload;
return {
...state,
items: state.items.filter(item => item.id !== id)
};
我希望这会有所帮助!