document.querySelector 在我的反应组件中不起作用

Question

function Slider() {
  const track=document.querySelector('.slide__track')//To access the div with class slide track
  console.log(track);
  return (
    <div className="slider">
      <i className="fas fa-chevron-left"></i>
      <div className="head">
        <h1 className="title">Based on your last search</h1>
        <h6>View more</h6>
      </div>
      <div className="slider_container">
        <ul className="slider__track">
          <li className="slider__items">
            <Card />
          </li>
        </ul>
      </div>
      <i className="fas fa-chevron-right"></i>
    </div>
  );
}

我无法使用 Slide__track 类访问 div。这里有什么问题？或者我如何访问该元素？

Answer 1

我认为这是因为它在 DOM 渲染之前运行。将轨道代码移至 useEffect 中。

import {useEffect} from "react";

function Slider() {

  useEffect(() => {
    const track=document.querySelector('.slide__track')//To access the div with class slide track
    console.log(track);
  });

  return (
    <div className="slider">
      <i className="fas fa-chevron-left"></i>
      <div className="head">
        <h1 className="title">Based on your last search</h1>
        <h6>View more</h6>
      </div>
      <div className="slider_container">
        <ul className="slider__track">
          <li className="slider__items">
            <Card />
          </li>
        </ul>
      </div>
      <i className="fas fa-chevron-right"></i>
    </div>
  );
}