UnhandledPromiseRejection

Question

Hello guys i create a website and everything works locally but when i deployed in heroku its not working and i cant find why thanks for the help

heroku error:

2022-02-10T03:13:43.014545+00:00 app[web.1]: (node:22) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with.catch(). To terminate the node process on unhandled promise rejection, use the CLI flag --unhandled-rejections=strict (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode ). (rejection id: 1) 2022-02-10T03:13:43.014570+00:00 app[web.1]: (node:22) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code. 2022-02-10T03:14:13.009344+00:00 heroku[router]: at=error code=H12 desc="Request timeout" method=GET path="/" host=websitechina.herokuapp.com request_id=ab93f3f6-9ccf-49e0-be7b-fe765239c47b fwd="61.219.114.7" dyno=web.1 connect=0ms service=30000ms status=503 bytes=0 protocol=https

index.js:

 const express = require('express') const app = express() const port = process.env.port || 3000 const nodemailer = require('nodemailer') //Importer la logique de la page d acceuil const generatorModele = require('./api/page/page-get') //ecouter la methode GET et la route app.get('/', async(req,res) => { const indexHtml = await generatorModele('index') res.send(indexHtml) }) app.get ('/tech', async(req,res) => { const techHtml = await generatorModele('tech') res.send(techHtml) }) app.get ('/contact', async(req,res) => { const contactHtml = await generatorModele('contact') res.send(contactHtml) }) app.get ('/signUp', async(req,res) => { const signUpHtml = await generatorModele('signUp') res.send(signUpHtml) }) //ecouter la methode Post et la route app.post('/', (req,res)=>{ console.log(req.body) //nodemailer not working yet i know // const transporter = nodemailer.createTransport({ service: 'gmail', auth: { user: '', pass: '' } }) transporter.sendMail(mailOptions, (error, info)=>{ if(error){ console.log(error) res.send('error') }else{ console.log('Email sent' + info.response) res.send('success') } }) }) //ecoute les requete du repertoire styles,js,images/ app.use('/styles', express.static('/Users/hi/code/dotfiles/dev/websitechina1/styles')) app.use('/images', express.static('/Users/hi/code/dotfiles/dev/websitechina1/images/')) app.use('/js', express.static('/Users/hi/code/dotfiles/dev/websitechina1/js/')) app.use(express.json()) //demarrer le serveur et ecouter un port donne app.listen(process.env.PORT || port,() => { console.log (`Example app listening on port ${port}`) })

app.js

 const menu = document.querySelector('#mobile-menu'); const menuLinks = document.querySelector('.navbar_menu'); menu.addEventListener('click', function(){ menu.classList.toggle('is-active'); menuLinks.classList.toggle('active'); }); const contactForm = document.querySelector('.contact-form') let fname = document.getElementById('fname') let lname = document.getElementById('lname') let email = document.getElementById('email') let country = document.getElementById('country') let subject = document.getElementById('subject') contactForm.addEventListener('submit', (e)=>{ e.preventDefault(); let formData = { fname: fname.value, lname: lname.value, email: email.value, country: country.value, subject: subject.value } let xhr = new XMLHttpRequest(); xhr.open('POST', '/') xhr.setRequestHeader('content-type','application/json') xhr.onload = function(){ console.log(xhr.responseText) if (xhr.responseText == 'success'){ alert('Email sent'); fname.value = ''; lname.value = ''; email.value = ''; country.value = ''; subject.value = ''; }else{ alert('Something went wrong') } } xhr.send(JSON.stringify(formData)) })

Answer 1

All uses of await that can reject must be handled in some way. They must either be surrounded by a try/catch or the caller of the async function must handle the rejection.

In this case, app.get() does not pay any attention to a returned/rejected promise from the async callback so you have to catch rejections locally. So, in this code:

//ecouter la methode GET et la route 
app.get('/', async(req,res) => {
    const indexHtml = await generatorModele('index')

    res.send(indexHtml)
    
})

You aren't catching a rejection from generatorModele() . You can do that like this:

//ecouter la methode GET et la route 
app.get('/', async(req,res) => {
    try {
        const indexHtml = await generatorModele('index');
        res.send(indexHtml);
    } catch(e) {
        console.log(e);
        res.sendStatus(500);
    }
});

All, your other uses of await need something similar.

---

FYI, when you have a problem like this and the error message doesn't point exactly to the problem, the first thing to do is make sure you're catching and logging all possible errors. This code I show above is one such example.