why cloud funtion in node js doesnt deploy propely - node.js

Question

here iam using a cloud functions to create users i am using a express module when i try to deploy this code it deploying to cloud funtions with message that Error : Funtions did not deploy properly
const express = require('express');
const functions = require('firebase-functions');
const admin = require('firebase-admin');
const serviceaccount = require('./ServiceAccountKey.json');
const app = express();
admin.initializeApp({
credential: admin.credential.cert(serviceaccount)
});
app.post('/',(req,res)=>{
if(req.method!== 'POST'){
res.status(400).send("what are u trying baby");
return;
}
admin.auth().createUser({
email:req.body.email,
password: req.body.pass,
}).then(function(userRecord){
res.send({'uid': userRecord.uid});
return;
}).catch(function(error){
res.send({'error': 'Try COrrect one baby'});
return;
});
return;
});
exports.register = funtions.Https.onRequest(app);
when i add this at end
module.exports = {
app
}
it showing funtion deployed but its not showing in cloud functions dashboard
what wrong am i doing here
here is the error what ima getting i cnat get whAT THE error is
⚠ functions[register(us-central1)]: Deployment error.
Function failed on loading user code. Error message: Code in file index.js can't be loaded.
Did you list all required modules in the package.json dependencies?
Detailed stack trace: Error: Cannot find module 'express'
at Function.Module._resolveFilename (module.js:476:15)
at Function.Module._load (module.js:424:25)
at Module.require (module.js:504:17)
at require (internal/module.js:20:19)
at Object.<anonymous> (/user_code/index.js:1:79)
at Module._compile (module.js:577:32)
at Object.Module._extensions..js (module.js:586:10)
at Module.load (module.js:494:32)
at tryModuleLoad (module.js:453:12)
at Function.Module._load (module.js:445:3)
Functions deploy had errors with the following functions:
register

Answer 1

You code never uses the firebase-functions modules to declare a Cloud Function. Your functions variable is going unused. You can't just export any function an expect it to run - it has to be built by the SDK.
If you have an express app to deploy, you need to export it via an HTTP type function:
exports.app = functions.https.onRequest(app);

Answer 2

First, I think you need to change the endpoint of the url. Don't just put '/'. Maybe like '/user/create'.
app.post('/user/create',(req,res)=>{
if(req.method!== 'POST'){
res.status(400).send("what are u trying baby");
return;
}
admin.auth().createUser({
email:req.body.email,
password: req.body.pass,
}).then(function(userRecord){
res.send({'uid': userRecord.uid});
return;
}).catch(function(error){
res.send({'error': 'Try COrrect one baby'});
return;
});
return;
});
exports.register = funtions.Https.onRequest(app);
And in your firebase.json you should rewrite the url :
{
"functions": {
...
},
"hosting": {
"public": "public",
"rewrites": [
{
"source": "/user/create",
"function": "register"
}
]
}
}
For more explanation, you can follow this tutorial.