async4express

Use it as you would normally. Only tested to work on Express 4.18, but I'm not going to lock the dependency. This definitely won't work (nor is it needed) with Express 5, but I can't guarantee it will work with future minor versions of Express either.

import express from 'async4express'

const app = express()

// Here, 'abc' is undefined. No async wrappers needed.
app.get('/', async (req, res, next) => {
    console.log(abc)
    res.send('')
})