我正在使一个简单的组件尝试利用useEffect和useReducer挂钩。除了数组中的所有项均未真正进入组件之外,其他所有内容似乎都正常运行。我已经在各种函数中完成了一些console.log语句,并且可以看到API调用成功,并且在事件下该函数的范围内有可用数据。但是,所有呈现的都是一个空盒子。我的代码是:
import React, { useReducer, useEffect } from "react";
import "./App.css";
const App = () => {
const [events, dispatch] = useReducer(
(state, action) => { switch (action.type) {
case "fetchEvents":
state = [ ...state, action.data];
return state;
case "removeEvent":
return state.filter((_, idx) => idx !== action.idx);
default:
console.log(state);
return state;
}
},
[]);
useEffect(async () => {
const response = await fetch("https://easynode-veohkvapci.now.sh/api/test");
const data = await response.json();
dispatch({type: "fetchEvents", data});
},[]);
console.log(events, 'log events');
return (
<div>
{events.map((event, idx) => (
<div key={event.event_url} style={{ border: "solid" }}>
<p>{event.name}</p>
<p>{event.date}</p>
<p>{event.description}</p>
<button onClick={() => dispatch({ type: "removeEvent", idx})}>Remove Event</button>
</div>
))}
</div>
);
};
export default App;
我应该在useReducer内部调用useEffect吗?我可能正在搞砸本应以异步方式发生的事情。
答案 0 :(得分:2)
从请求中获得的数据是一个数组,因此您需要确保在化简器的fetchEvents
情况下也将其分布。
const [events, dispatch] = useReducer((state, action) => {
switch (action.type) {
case "fetchEvents":
state = [...state, ...action.data];
return state;
case "removeEvent":
return state.filter((_, idx) => idx !== action.idx);
default:
return state;
}
}, []);