[[server.js]] function renderPartial(res, view, params = {}) { return new Promise((resolve, reject) => { res.app.render(view, params, (err, html) => { if (err) return reject(err); resolve(html); }); }); } app.get('/tennis', async (req, res) => { const chapter = req.query.chapter_num; let tennisHtml = ''; if (chapter === '1') { tennisHtml = await renderPartial(res, 'tennis/rule'); } else if (chapter === '2') { tennisHtml = await createAdmin(req.query); tennisHtml += await createParticipantTable(); // DBから生成されたテーブル } else if (chapter === '5') { tennisHtml = await renderPartial(res, 'tennis/information'); } else { tennisHtml = await createParticipantTable(); // DBから生成されたテーブル } res.render('layout', { hicon: hosticon(), tennisHtml }); });