Data Structure that manages client connections in lobby - Useful for WebSockets

channel.js

// Pradyumn Nukala
// Safely manages connections
class Channel {
    constructor() {
        this.receivers = {};
        this.senders = {};
        this.default = {};
    }

    // ***********************************
    // ****** Channel Checks *************
    // ***********************************
    // Find Item in Array, 
    // options = exists(bool): check exists or not, 
    //           client: client to check, 
    //           noLog: bool for logging on/off
    //           target: receivers/senders/default
    clientCheck(options = {}, callback) {
        // Check if item exists
        if (options.exists) {
            // Check Target -- Receivers
            if (options.target === "Receivers") {
                if (this.receivers.hasOwnProperty(options.client.id)) {
                    // Validate Callback
                    if (typeof callback == "function") {
                        return callback();
                    }
                } else {
                    // Check if log
                    if (options.logging) {
                        console.log("Item not found in array when checking if it exists.");
                    }
                    return false;
                }
            }
            // Check Target -- Senders
            else if (options.target === "Senders") {
                if (this.senders.hasOwnProperty(options.client.id)) {
                    // Validate Callback
                    if (typeof callback == "function") {
                        return callback();
                    }
                } else {
                    // Check if log
                    if (options.logging) {
                        console.log("Item not found in array when checking if it exists.");
                    }
                    return false;
                }
            }
            // Check Target -- Default
            else if (options.target === "Default") {
                if (this.default.hasOwnProperty(options.client.id)) {
                    // Validate Callback
                    if (typeof callback == "function") {
                        return callback();
                    }
                } else {
                    // Check if log
                    if (options.logging) {
                        console.log("Item not found in array when checking if it exists.");
                    }
                    return false;
                }
            }
            // Check if item doesnt exist
        } else {
            // Check Target -- Receivers
            if (options.target === "Receivers") {
                if (!this.receivers.hasOwnProperty(options.client.id)) {
                    // Validate Callback
                    if (typeof callback == "function") {
                        return callback();
                    }
                } else {
                    // Check if log
                    if (options.logging) {
                        console.log("Item not found in array when checking if it exists.");
                    }
                    return false;
                }
            }
            // Check Target -- Senders
            else if (options.target === "Senders") {
                if (!this.senders.hasOwnProperty(options.client.id)) {
                    // Validate Callback
                    if (typeof callback == "function") {
                        return callback();
                    }
                } else {
                    // Check if log
                    if (options.logging) {
                        console.log("Item not found in array when checking if it exists.");
                    }
                    return false;
                }
            }
            // Check Target -- Default
            else if (options.target == "Default") {
                if (!this.default.hasOwnProperty(options.client.id)) {
                    // Validate Callback
                    if (typeof callback == "function") {
                        return callback();
                    }
                } else {
                    // Check if log
                    if (options.logging) {
                        console.log("Item not found in array when checking if it exists.");
                    }
                    return false;
                }
            }
        }
    }

    toMap() {
        return {
            default: this.default,
            senders: this.senders,
            receivers: this.receivers,
        };
    }

    // ***********************************
    // ****** Channel Management *********
    // ***********************************
    // Add Item if it Doesnt Exist
    safeAdd(client, target, logging = true) {
        // Check Options
        var options = {
            exists: false,
            client: client,
            target: target,
            logging: logging
        };

        // Run Check
        this.clientCheck(options, () => {
            // Check Target -- Receivers
            if (target === "Receivers") {
                this.receivers[client.id] = client;
            }
            // Check Target -- Senders
            else if (target === "Senders") {
                this.senders[client.id] = client;
            }
            // Check Target -- Default
            else if (target == "Default") {
                this.default[client.id] = client;
            }

            // Check if log
            if (logging) {
                console.log("Item safely added");
            }
            return true;
        });
        return false;
    }

    // Copy Map to Target
    safeCopy(map, client) {

        // Check Target -- Receivers
        this.receivers = map["receivers"];
        
        // Check Target -- Senders
        this.senders = map["senders"];

        // Check Target -- Default
        this.default = map["default"];

        // Check Client Status - Initialize
        if (client["status"]["code"] === 1) {
            // Update Lobby
            this.shift(client, "Default");
        }
        // Check Client Status - Sending
        else if (client["status"]["code"] === 10) {
            // Add to senders, and check
            this.shift(client, "Senders");
        }
        // Check Client Status - Receiving
        else if (client["status"]["code"] === 20) {
            // Add to receivers, and check
            this.shift(client, "Receivers");
        }
    }

    // Delete Item in Array
    safeRemove(client, target, logging = true) {
        // Check Options
        var options = {
            exists: true,
            client: client,
            target: target,
            logging: logging
        };

        // Run Check
        this.clientCheck(options, () => {
            // Check Target -- Receivers
            if (target === "Receivers") {
                delete this.receivers[client.id];
            }
            // Check Target -- Senders
            else if (target === "Senders") {
                delete this.senders[client.id];
            }
            // Check Target -- Default
            else if (target == "Default") {
                delete this.default[client.id];
            }

            // Check if log
            if (logging) {
                console.log("Item safely deleted");
            }
            return true;
        });
        return false;
    }

    // Delete All provided arrays
    leave(client) {
        this.safeRemove(client, "Senders");
        this.safeRemove(client, "Default");
        this.safeRemove(client, "Receivers");
    }

    // Move Items from another ClientArray
    shift(client, target) {
        // Check Target -- Receivers
        if (target === "Receivers") {
            this.safeAdd(client, "Receivers");
            this.safeRemove(client, "Senders");
            this.safeRemove(client, "Default");
        }
        // Check Target -- Senders
        else if (target === "Senders") {
            this.safeAdd(client, "Senders");
            this.safeRemove(client, "Receivers");
            this.safeRemove(client, "Default");
        }
        // Check Target -- Default
        else if (target == "Default") {
            this.safeAdd(client, "Default");
            this.safeRemove(client, "Senders");
            this.safeRemove(client, "Receivers");
        }
    }

    // Returns Combined Count of Lobby
    size() {
        return Object.keys(this.default).length +
            Object.keys(this.senders).length +
            Object.keys(this.receivers).length;
    }
}

module.exports = Channel;