nodejs tcp proxy authentication - node.js

Question

I am using a nodejs module called tcp-proxy to pipe the requests from client to proxy server in order to proxy the requests.
I want this proxy to work only when the user provides the username and password, so I modified my code to make the client send proxy authentication header before proceeding.
Here is my javascript code:
var tcpProxy = require('tcp-proxy');
var server = tcpProxy.createServer({
target: {
host: 'HOST'
port: 'PORT'
}
});
server.listen(8000);
server.on('connection', (socket) => {
socket.on('data', (data) => {
if(!authorized(data, socket)) {
socket.write('HTTP/1.1 407 Proxy Authentication Required\nProxy-Authenticate: Basic realm=""\nConnection: keep-alive');
socket.write('\n\r\n');
socket.end();
}
});
});
function authorized(data, socket) {
if(socket.auth){
return true;
}
for(var i=0; i<=10; i++) {
if(data.toString().split('\r\n')[i]) {
var headerType = data.toString().split('\r\n')[i].split(':')[0];
if(headerType == "Proxy-Authorization") {
var header = data.toString().split('\r\n')[i].split(':')[1];
var creds = new Buffer(header.split(' ')[2], 'base64').toString().split(':');
var username = creds[0];
var password = creds[1];
if(username === "USERNAME" && password === "PASSWORD") {
socket.auth = true;
return true;
} else {
return false;
}
}
}
}
return false;
}
Everything is working fine in Chrome and Mozilla Firefox, but in Safari and some other client applications it doesn't work as expected.
I've tried to debug and found that when making https request from Safari browser (with proxy set in Wifi settings on Mac) the Proxy-Authorization header is missing from the request, and the same happens with the some other client application which have the option to use proxy server.
Since my proxy server is supposed to drop the request if it doesn't find the header it does that for Safari.
Why does this happen? Any solution to get it working on all browsers and applications?