减速器中的React Redux Assign Arrow Function Warning

Question

有人能告诉我为什么在我的React应用程序中收到此警告吗？

src/reducers/post.js第3:1行：在导出为模块默认之前，将箭头函数分配给变量

import { FETCH_ALL, CREATE, UPDATE, DELETE } from '../constants/actionTypes';
export default (posts = [], action) => {
switch (action.type) {
case FETCH_ALL:
return action.payload;
case UPDATE:
return posts.map((post) => post._id === action.payload._id ? action.payload : post);
case CREATE:
return [ ...posts, action.payload];
case DELETE:
return posts.filter((post) => post._id !== action.payload);
default:
return posts;
}
}

Answer 1

不能导出默认值和同时声明变量。试试这个：

const variable = (posts = [], action) => {
switch (action.type) {
case FETCH_ALL:
return action.payload;
case UPDATE:
return posts.map((post) => post._id === action.payload._id ? action.payload : post);
case CREATE:
return [ ...posts, action.payload];
case DELETE:
return posts.filter((post) => post._id !== action.payload);
default:
return posts;
}
}
export default variable

或者使用传统命名函数导出默认值：

export default function variable(posts = [], action) {
switch (action.type) {
case FETCH_ALL:
return action.payload;
case UPDATE:
return posts.map((post) => post._id === action.payload._id ? action.payload : post);
case CREATE:
return [ ...posts, action.payload];
case DELETE:
return posts.filter((post) => post._id !== action.payload);
default:
return posts;
}
}

Answer 2

为函数添加变量：

export default const variable = (posts = [], action) => {
switch (action.type) {
case FETCH_ALL:
return action.payload;
case UPDATE:
return posts.map((post) => post._id === action.payload._id ? action.payload : post);
case CREATE:
return [ ...posts, action.payload];
case DELETE:
return posts.filter((post) => post._id !== action.payload);
default:
return posts;
}
}

JavaScript必须知道您导出的是什么