Get Express app's response header in Angular 7 client - node.js

Question

I've been trying to access the http response header from a NodeJS app in the Angular 7 client code, but I'm unable to retrieve it. I've tried every solution I found on Stack Overflow. I still keep getting an empty header back in the browser. But it works fine on Postman.
I'm attaching the browser console log below:
headers: HttpHeaders
lazyInit: ƒ ()
lazyUpdate: null
normalizedNames: Map(0)
size: 0
__proto__: Map
[[Entries]]: Array(0)
length: 0
Server-side code:
app.js
const express = require('express');
const bodyParser = require('body-parser');
const cors = require('cors');
const route = require('./routes/route');
const { mongoose } = require('./db/mongoose');
const app = express();
app.use(bodyParser.json());
app.use(cors({
'allowedHeaders': ['sessionId', 'Content-Type', 'x-auth', 'Authorization'],
'exposedHeaders': ['sessionId', 'x-auth', 'Authorization'],
'origin': '*',
'methods': 'GET,HEAD,PUT,PATCH,POST,DELETE,OPTIONS',
'preflightContinue': false
}));
// app.options('*', cors());
app.use(route);
app.listen(3000);
controller.js
exports.signupUser = (req, res, next) => {
let user = new UserModel({
email: req.body.email,
password: req.body.password
});
user.save().then((user) => {
return user.generateAuthToken();
}).then((token) => {
res.header({
'Access-Control-Allow-Headers': 'Origin, X-Requested-With, Content-Type, Accept, Authorization',
'Access-Control-Expose-Headers': 'Authorization',
'Access-Control-Allow-Methods': 'GET,PUT,POST,DELETE,PATCH,OPTIONS',
'Access-Control-Allow-Credentials': 'true',
'x-auth': token
}).send(user);
}).catch((err) => {
res.status(400).send(err);
});
};
angular 7 code:
auth.service.ts
import { Injectable } from '#angular/core';
import { HttpClient } from '#angular/common/http';
#Injectable()
export class AuthService {
token: string;
constructor(private http: HttpClient) { }
signup(email: string, password: string) {
this.http
.post('http://localhost:3000/signup', { email, password }, {observe: 'response'})
.subscribe((response) => {
console.log(response);
});
}
}

Answer 1

How are you attempting to access your header on the client side?
The response.headers from your example is an instance of HttpHeaders. The headers arent visible as properties on the headers object itself but you can access them like this:
this.http
.post('http://localhost:3000/signup', { email, password }, {observe: 'response'})
.subscribe((response) => {
let contentTypeHeader = response.headers.get("content-type");
console.log(contentTypeHeader);
});