Copy LeetCode Solution to clipboard

leetcode-solution.user.js

// ==UserScript==
// @name         Copy LeetCode Solution to clipboard
// @namespace    https://gist.github.com/jizusun/84495bd63e2ed4a33823a9cfc728a810
// @version      0.3
// @description  Better format to paste into Notion
// @author       You
// @match        https://leetcode.com/problems/*/solution/
// @grant        GM_setClipboard
// ==/UserScript==

(function() {
    'use strict';

    function copyDivToClipboard(str) {
        // GM_setClipboard(result, 'html');

        function listener(e) {
            e.clipboardData.setData("text/html", str);
            e.clipboardData.setData("text/plain", str);
            e.preventDefault();
        }
        document.addEventListener("copy", listener);
        document.execCommand("copy");
        document.removeEventListener("copy", listener);

    }

    const processKatex = (elem) => {
        elem.querySelectorAll('.katex').forEach( i => {
            const val = i.querySelector('annotation').innerHTML.trim()
            i.innerHTML= '$$' + val + '$';
        })
    }

    const processImage = (elem) => {
        elem.querySelectorAll('img').forEach(i => {
            const src = i.src
            i.setAttribute('src', src)
        })
    }

    const processIframe = (elem) => {
        elem.querySelectorAll('iframe').forEach( i=> {
            const url = i.src
            const parent = i.parentNode
            var a = document.createElement('a');
            var linkText = document.createTextNode(url);
            a.appendChild(linkText);
            a.title = url;
            a.href = url;
            parent.insertBefore(a, i)
        })
    }

    const removeH2 = (elem) => {
        const h2 = elem.querySelector('h2')
        const hr = elem.querySelector('hr')
        h2 && elem.removeChild(h2)
        hr && elem.removeChild(hr)
        return h2
    }

    const copySolution = (solutionElem) => {
        const clonedElem = solutionElem.cloneNode(true)
        removeH2(clonedElem)
        processKatex(clonedElem)
        processIframe(clonedElem)
        processImage(clonedElem)
        copyDivToClipboard(clonedElem.innerHTML)
        console.log('Solution Copied');
    }

    const MutationObserver = window.MutationObserver || window.WebKitMutationObserver;
    const observer = new MutationObserver(function(mutations, observer) {
        const contentElem = document.querySelector("#solution *[class^='content__']");
        if (contentElem) {
            const solutionElem = contentElem.querySelector(':first-child')
            const btn = document.createElement("BUTTON");
            btn.innerHTML = "Copy solution to clipboard";
            btn.addEventListener('click', e => copySolution(solutionElem))
            contentElem.insertBefore(btn, solutionElem)
            observer.disconnect();
        };
    });

    observer.observe(document, {
        subtree: true,
        attributes: true
    });

})();