Trouble converting JS to Typescript

Question

Original JS code:

net.createServer(function (socket) {

  // Identify this client
  socket.name = socket.remoteAddress + ":" + socket.remotePort

My try of convertion:

class Peer {
public sock: net.Socket;
public name: string;
public pid: number;
constructor(sock:net.Socket,name:string)
{
    sock = sock;
    name = name;
}
}



// Load the TCP Library

var cid: number =0;
// Keep track of the chat clients
var clients: Peer[] = [];

// Start a TCP Server
net.createServer(function (socky: net.Socket) {
  // Identify this client
  var peer:Peer=new Peer(socky,"");
  peer.name = peer.sock.remoteAddress + ":" + peer.sock.remotePort

First code runs smoothly without any problems, second output this:

C:\Users\Morgan\Desktop\typescript-starter\dist\app.js:21
    peer.name = peer.sock.remoteAddress + ":" + peer.sock.remotePort;
                    ^

TypeError: Cannot read property 'remoteAddress' of undefined
    at Server.<anonymous> (C:\Users\Morgan\Desktop\typescript-starter\dist\app.j
s:21:21)
    at emitOne (events.js:96:13)
    at Server.emit (events.js:188:7)
    at TCP.onconnection (net.js:1459:8)

And here is the translation from TS to JS of that piece of code:

var Peer = (function () {
    function Peer(sock, name) {
        sock = sock;
        name = name;
    }
    return Peer;
}());
var cid = 0;
var clients = [];
net.createServer(function (socky) {
    var peer = new Peer(socky, "");
    peer.name = peer.sock.remoteAddress + ":" + peer.sock.remotePort;

Complete .TS file: http://pastebin.com/1UUtSzgz

Complete .JS file: http://pastebin.com/X5YAZjwu

Complete TS to JS converted file: http://pastebin.com/H25W7amh

I've tried setting accessors for the socket, it never worked. if all the work is done on socky it works, but if i pass by peer, the undefined error pops.

Daniel Rosenwasser · Accepted Answer · 2016-08-29 01:48:16Z

2

Your Peer constructor isn't setting its instance members. It's setting the local parameters sock and name.

You probably meant to write something closer to this:

class Peer {
    public sock: net.Socket;
    public name: string;
    public pid: number;

    constructor(sock: net.Socket, name: string) {
        this.sock = sock;
        this.name = name;
    }
}

As a tip, TypeScript has a shorthand because this sort of code gets cumbersome to write.

class Peer {
    public pid: number;

    constructor(public sock: net.Socket, public name: string) {
    }
}

Notice the public modifier on each parameter. That automatically creates a public property for each parameter.

answered Aug 29, 2016 at 1:48

Daniel Rosenwasser

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1 Comment

Morgan Fouque Over a year ago

Fixed everything, thank you very much! I'm new to this, learning the hard way, your tip is very appreciated! :) Validating in 2 minutes!

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