NodeJS IIFE 返回变量不可用于 res.render 函数

Question

对于水疗中心来说，这是有点刮擦，我的最终目标是渲染结果并将下载作为Excel功能。但是，到目前为止，我还远远不够，我可以将刮擦的结果记录到控制台，但是我遇到的问题将它们完全渲染到了前端。

刮擦零件是通过iife完成的，但是Express Res.Render无法访问IIFE的返回值，它会引发以下错误＆gt;＆gt; “ ReferenceError：jobtitles未定义” ATR行11（Res.Render试图访问此位：

let jobTitles = await page.$$eval('ul li h3 a', titles => {
  return titles.map(title => title.innerText);

完整代码：

const puppeteer = require('puppeteer');
const express = require('express');
const app = express();
const path = require('path');
const router = express.Router();

app.set('view engine', 'ejs');


app.get('/', function(req, res) {
res.render('pages/index', { key: `Job Titles on first page of Workable are: 
${jobTitles.join(', ')}` });
});


app.use('/', router);
app.listen(process.env.port || 3000);

console.log('Running at Port 3000');
(async () => {
try {
const browser = await puppeteer.launch();
const page = await browser.newPage();
const navigationPromise = page.waitForNavigation();

await page.goto('https://jobs.workable.com/');
await page.setViewport({ width: 1440, height: 744 });
await navigationPromise;

await page.waitForSelector('ul li h3 a');
let jobTitles = await page.$$eval('ul li h3 a', titles => {
  return titles.map(title => title.innerText);
});
console.log(`Job Titles on first page of Workable are: ${jobTitles.join(', ')}`);
await browser.close();
} catch (e) {
console.log(`Error while fetching workable job titles ${e.message}`);
}
})();

控制台日志语句运行良好，返回结果良好，因此我如何构建以获取此功能来获得它用expressjs渲染？