Question

useEffect(() => {
  // this part makes error  "=>" (Expected to return a value at the end of arrow function.)

  if (autoSlide) {
    const interval = setInterval(() => {
      refCurrentSlide.current.setCurrentSlide(
        refCurrentSlide.current.currentSlide + 1 >=
          refTotalSlide.current.totalSlide
          ? 0
          : refCurrentSlide.current.currentSlide + 1
      );
    }, INTERVAL_TIME);
    return () => clearInterval(interval);
  }
}, [autoSlide, INTERVAL_TIME]);

Answer 1

enter code here useEffect(() => {

// This gets called after every render, by default
// (the first one, and every one after that)
console.log('render!');

// If you want to implement componentWillUnmount,
// return a function from here, and React will call
// it prior to unmounting.
return () => console.log('unmounting...');

})

返回“我是一个生命周期演示”； }

如何修复这个 useEffect 返回？

1 个答案: