Node.js read TCPSocket and write to a variable - node.js

Question

I've got a litte problem with my code snipet. I wrote a example to learn the TCP Socket Communication for a project. For the moment i can send a TCP Socket and read the answer, but i want to use the answer in other software parts. For that i tried to use the variable socketmessage but this doesn't work. Does anyone have the answer for my problem? Thanks a lot
var net = require('net');
var client = new net.Socket();
var HOST='127.0.0.1';
var PORT='20000';
var MSG="{\"REQUEST\":\"STATUS\"}";
var socketmessage;
socketmessage=getSocketMessage(MSG);
console.log ("Socket Message: " + socketmessage);
function getSocketMessage(tcpmsg){
var outData;
client.connect(PORT, HOST, function() {
console.log("Client: " + tcpmsg);
client.write(tcpmsg);
});
client.setTimeout(5000, function() { client.destroy(); });
client.on('data', function(data) {
console.log('Server: ' + data);
outData = data.toString('utf8');
console.log ("Socketmessage: " + outData);
client.destroy();
});
//Add a 'close' event handler for the client socket
client.on('close', function() {
console.log('Connection closed');
});
// Add a 'error' event handler for the client socket
client.on('error', function(error) {
console.log('Error Connection: ' + error);
});
return outData;
}
Terminal:
Socket Message: undefined
Client: {"REQUEST":"STATUS"}
Server: {"STATUS":0.000000}

Answer 1

This is because function getSocketMessage is asynchronous. You are trying to return the received message. The function returns immediately, outData being undefined then. Its value is
set when data arrives from server. The network I/O is evented, the event you use is data
client.on('data', function(data) {
The received message can only be handled properly inside the event-handler for data. You would have to call your other part from here itself.

Answer 2

You can create a read stream and once the stream ends you may process the data.
var readStream = fs.createReadStream(path of the file, 'utf8'); //you can use path.join(loc, filename)
var data = '';
readStream.on('data', function(chunk:any) {
data += chunk;
}).on('end', function() {
let gotContent = data.toString(); //
doWhatEver(gotContent) //the method is async or promose
then(function(result){
console.log(result); //desired output
})
});