YTMusic_export.js

function findChildByClass(el, clazz, deep) {
    let children = Array.isArray(el) ? el : Array.from(el.childNodes);
    if (deep === true) {
        for (let i = 0; i < children.length; ++i) {
            let res = findChildByClass(children[i], clazz, true);
            if (res) return res;
        }
    }
    return children.find(i => Array.from(i.classList || []).indexOf(clazz) != -1);
}

function saveAsFile(data, fileName, mimeType) {
    let a = document.createElement('a');
    document.body.append(a);
    a.style = 'display: none';
    let blob = new Blob([data], {type: mimeType}),
        href = URL.createObjectURL(blob);
    a.href = href;
    a.download = fileName;
    a.click();
    URL.revokeObjectURL(href);
    a.remove();
}

(function () {
    let collectionName = 'Неизвестная',
        metadata = document.getElementsByClassName('metadata')[0];
    if (metadata) {
        let el = findChildByClass(metadata, 'title', true);
        if (el) {
            collectionName = el.textContent;
        }
    }

    let data = [],
        contents = document.getElementById('contents'),
        table = Array.from(contents.childNodes[0].childNodes).find(el => el.id == 'contents');
    table.childNodes.forEach((el) => {
        let columns = findChildByClass(el, 'flex-columns'),
            childNodes = Array.from(columns.childNodes);
        let titleColumn = findChildByClass(childNodes, 'title-column'),
            secondaryColumn = findChildByClass(childNodes, 'secondary-flex-columns');
        let title = findChildByClass(titleColumn, 'yt-formatted-string', true),
            group = findChildByClass(secondaryColumn, 'yt-formatted-string', true);
        if (title && group) {
            data.push(title.textContent + ', ' + group.textContent);
        }
    });

    // Yandex Music: $('.d-icon_heart').click();
    console.log(`Collection "${collectionName}", total rows := ${data.length}`);
    saveAsFile(data.join('\r\n'), collectionName + '.txt', 'text/plain; charset=utf-8');
})();