JavaScript object referencing

Question

So, I'm pretty new to JavaScript, and while I know the little tricks to do things like this in Java the same tricks don't really apply here, or at least I can't really figure out how to use them, so I'm currently using two objects in the form of collections:

var ConnectedClients_socket = {};
var ConnectedClients_networkId = {};

The hold a key/value pair to link a networkID to a client and then a duplicated object that uses the socket as a key. Any optimizations would be great, I'll be grabbing the client by the socket and ID a lot throughout the application.

On to the problem:

Upon disconnection I need to remove the client instance from the ConnectedClients_networkId object. From my understanding this is done using the delete keyword.

Here's the code I'm currently trying to use for this:

console.log('socket disconnected');
delete Client.ConnectedClients_networkId[Client.ConnectedClients_socket[socket].getNetworkId()];
delete Client.ConnectedClients_socket.socket;

However this is giving me the following error:

TypeError: Cannot call method 'getNetworkId' of undefined

which shows that

Client.ConnectedClients_socket[socket]

is returning undefined, while Client.ConnectedClients_socket.socket is being removed successfully a line later. I've looked up a few different pages on getting a value from a key in JavaScript, and I don't see what I'm doing wrong.

Here's the constructor for a client:

var Client = function(networkId, socket, ...) {
 this.networkId = networkId;
 this.socket = socket;
 ...
 ConnectedClients_socket.socket = this;
 ConnectedClients_networkId.networkId = this;
}

• Scimonster: Nice job describing your problem; +1.
• Bitwise Creative: Indeed, very clean description. +1
• Deshan: Isnt the line Client.ConnectedClients_socket[socket].getNetworkId() should be Client.ConnectedClients_socket.socket.getNetworkId() ?

Answer 1

Quotes?

Client.ConnectedClients_socket['socket']

However, there is no need for this notation here.

Client.ConnectedClients_socket.socket

Is fine.

Bracket notation can be used for accessing members with special characters or by variable value.

Client.ConnectedClients_socket['someArr[]']

or

var x = 'socket';
Client.ConnectedClients_socket[x]

Answer 2

You need to use dot notation there.

 delete Client.ConnectedClients_networkId[Client.ConnectedClients_socket.socket.getNetworkId()];

Bracket notation will parse it as JavaScript, so it's useful for dynamically getting a property.

• Hobbyist: I'm not exactly sure I understand how this works. I've read in numerous areas that the bracket and dot notation were completely interchangeable. Could you please link me somewhere that this is explained in detail?
• Scimonster: stackoverflow.com/questions/1168807/…
• Lewis: @Christian.tucker Bracket notation accepts string only.
• RobG: @Orion—bracket notation "accepts" any expression, but as property names are strings the expression will be evaluated and then converted to a string using the internal ToString method.