获取HTML页面有多少种标签

前端小测-JS 算法题目(数组相关):

注意是获取页面有多少种标签,不是多少个

已知如下 html 页面:

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<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <div>
      <header>
        获取HTML页面有多少种标签
        <div>
          <ul>
            <li>1</li>
            <li>2</li>
            <li>3</li>
          </ul>
        </div>
      </header>
      <section>
        <span></span>
        <p></p>
        <p></p>
      </section>
      <footer>
        <div>
          <h1></h1>
          <h2></h2>
        </div>
      </footer>
    </div>
  </body>
</html>

获取页面多少种标签方法:

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console.log("result", [...document.querySelectorAll("*")]);

console.log(new Set([...document.querySelectorAll("*")]));

const result = [...document.querySelectorAll("*")].map((item) => item.nodeName);

console.log("result", [...new Set(result)].length);

const findHtmlTagsName = () => {
  return [
    ...new Set(
      [...document.querySelectorAll("*")].map((item) => item.nodeName)
    ),
  ].length;
};

console.log("result length", findHtmlTagsName());

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