用到了jsdom库，直接现成处理html标签结构，只需要关心format格式化样式即可。

比较简易，待后续优化，目前只是短时间批量转换html文件。

const { JSDOM } = require('jsdom');const getText = (htmlString) => {if (!htmlString) return "";if (typeof (htmlString) !== 'string') {htmlString = htmlString.textContent;}return htmlString.replaceAll(/\s+/g, ' ');
}
const format = {h1: (element) => {return `\n# ${getText(element)}\n`;},h2: (element) => {return `\n## ${getText(element)}\n`;},h3: (element) => {return `\n### ${getText(element)}\n`;},h4: (element) => {return `\n#### ${getText(element)}\n`;},h5: (element) => {return `\n##### ${getText(element)}\n`;},h6: (element) => {return `\n###### ${getText(element)}\n`;},code: (element) => {let className = element.getAttribute('class') || '';className = className.replace('language-', '');return '\n```' + className + "\n" + element.textContent + "\n```\n";},blockquote: (element) => {let result=reformat(element);let arr=result.split("\n\n");return "> "+arr.join("> ");},p: (element) => {return `\n${getText(reformat(element))}\n`;},strong: (element) => {return `**${getText(element)}**`},a: (element) => {return `[${getText(element)}](${element.getAttribute("href")})`},s: (element) => {return `~~${getText(element)}~~`},em: (element) => {return `*${getText(element)}*`},img: (element) => {return `![1](${element.getAttribute("src")})`;},ol: (element) => {let result = "\n";let index = 1;for (let child of element.childNodes) {if (child.tagName && child.tagName.toLowerCase() === 'li') {result += `${index++}. ${getText(child)}\n`;}}return result;},ul: (element) => {let result = "\n";for (let child of element.childNodes) {if (child.tagName && child.tagName.toLowerCase() === 'li') {result += `- ${getText(child)}\n`;}}return result;},table: (element) => {let result = "\n";let row = 0;const getTRString = (tr) => {let str = "|";if (tr) {for (let td of tr.childNodes) {if (td.tagName && td.tagName.toLowerCase() === 'td') {str += " " + getText(td) + "   |"}}}if (str.length == 1) str = '| |'return str + "\n";}for (let child of element.childNodes) {if (child.tagName) {for (let tr of child.childNodes) {if (tr.tagName && tr.tagName.toLowerCase() === 'tr') {result += getTRString(tr);row++;if (row == 1) {//这个是markdown识别表格的标识  |---|---|--|----|--|  一般情况下宽度会自适应result += "|"for (let td of tr.childNodes) {if (td.tagName && td.tagName.toLowerCase() === 'td') {result += "---|";}}result += "\n";}}}}}return result;}
}
//二次格式化，如<p><strong>123</strong></p>  第一次格式化只会匹配到p，因此需要二次格式化处理内在元素
const reformat = (element) => {let result = "";for (let child of element.childNodes) {if (child.tagName && format[child.tagName.toLowerCase()]) {//拦截命中result += format[child.tagName.toLowerCase()](child);} else {//没有需要处理的标签，深入处理result += getText(child.textContent);}}return result;
}
const dp = (element) => {let markdownStringArray = [];for (let child of element.childNodes) {if (child.tagName) {let functionName = child.tagName.toLowerCase();//取出标签名称if (format[functionName]) {//拦截命中markdownStringArray.push(format[functionName](child));} else {//没有需要处理的标签，深入处理markdownStringArray = markdownStringArray.concat(dp(child));}}}return markdownStringArray;
}exports.html_to_markdown = (htmlString) => {const dom = new JSDOM(htmlString);const body = dom.window.document.body;let arr = dp(body);return arr.join("");
}

使用方法

const markdownString= html_to_markdown(html);