为什么我的状态无法使用React Hooks更新? [英] Why is my state not being updated using React Hooks?

问题描述

我正在尝试将状态设置为从API提取的数据.但是，当我用console.log记录状态(在这种情况下为 items )时，它将返回一个空数组.

I'm trying to set my state to data fetched from an API. However when I console.log the state (items in this instance), it returns an empty array.

这是我的代码:

const Search = () => {
  const apiKey = 'xxxxxxx';
  const [input, setInput] = useState('');
  const [items, setItems] = useState([]);

  const handleSubmit = (e) => {
    searchAPI();
  };

  const searchAPI = async () => {
    const res = await fetch(`http://www.omdbapi.com/?apikey=${apiKey}&s=${input}`);
    const data = await res.json();
    setItems([data.Search]);
    console.log(items)
  };

  return (
    <form>
      <input onChange={(e) => setInput(e.target.value)}></input>
      <Link to={{ pathname: '/results', state: items }}>
        <button type="submit" onClick={handleSubmit}>
          search
        </button>
      </Link>
    </form>
  );
};

推荐答案

因为setState是异步的

Because setState is asynchronous

setState()并不总是立即更新组件.它可能批处理或将更新推迟到以后.这使得阅读this.state在调用setState()之后立即陷入陷阱

setState() does not always immediately update the component. It may batch or defer the update until later. This makes reading this.state right after calling setState() a potential pitfall

https://reactjs.org/docs/react-component.html#setstate

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