<p>我正在学习React，特别是学习useEffect。</p> <p>我无法弄清楚的是为什么useEffect跳过了数组的最后一个元素。</p> <p>请问有人可以友好地解释一下为什么以及如何修复吗？</p> <pre class="brush:php;toolbar:false;">let users = ['Oliver', 'Thomas', 'George', 'William'] export default function App() { const [index, setIndex] = useState(0); console.log('RENDER'); useEffect(() =&gt; { if (index === users.length - 1) { return } setTimeout(() =&gt; setIndex(index =&gt; index + 1), 2000) console.log('Hello ' + users[index]); console.log('Side Effect RUNS!'); }, [users[index]]) }</pre> <p><br /></p>

let users = ['Oliver', 'Thomas', 'George', 'William']
export default function App() {
  const [index, setIndex] = useState(0);
  console.log('RENDER');
  useEffect(() => {
    if (index === users.length - 1) {
      return
    }
    setTimeout(() => setIndex(index => index + 1), 2000)
    console.log('Hello ' + users[index]);
    console.log('Side Effect RUNS!');
  }, [index]) // 更改为 `[index]`

}