Use modern ES2015 features such as Set, Map, and arrow functions

Author: akainth015

pynetworktables2js/js/networktables.js

@@ -1,57 +1,18 @@
 "use strict";
 
-var NetworkTables = new function () {
-	
+const NetworkTables = new function () {
+
+
+	let robotAddress;
+	let robotConnected;
+	let socketOpen;
+	let socket;
+
 	if (!("WebSocket" in window)) {
 		alert("Your browser does not support websockets, this will fail!");
 		return;
 	}
-	
-	//
-	// javascript map implementation
-	// map functions copied from d3 (BSD license: Mike Bostock)
-	//
-	
-	var d3_map_proto = "__proto__", d3_map_zero = "\x00";
-	
-	// we use encodeURIComponent/decodeURIComponent to allow weird values
-	// into the maps we create
-	
-	function d3_map_escape(key) {
-		return (key += "") === d3_map_proto || key[0] === d3_map_zero ? d3_map_zero + encodeURIComponent(key) : encodeURIComponent(key);
-	}
-	
-	function d3_map_unescape(key) {
-		return (key += "")[0] === d3_map_zero ? decodeURIComponent(key.slice(1)) : decodeURIComponent(key);
-	}
-	
-	var d3_map = function() {
-		
-		this._ = Object.create(null); 
-		
-		this.forEach = function(f) {
-			for (var key in this._) f.call(this, d3_map_unescape(key), this._[key]);
-		};
-		
-		this.get = function(key) {
-			return this._[d3_map_escape(key)];
-		};
-		
-		this.getKeys = function() {
-			var keys = [];
-			for(var key in this._) keys.push(d3_map_unescape(key));
-			return keys;
-		};
-		
-		this.has = function(key) {
-			return d3_map_escape(key) in this._;
-		};
-		
-		this.set = function(key, value) {
-			return this._[d3_map_escape(key)] = value;
-		};
-	};
-	
+
 	//
 	// Utility functions
 	//
@@ -61,7 +22,7 @@ var NetworkTables = new function () {
     	is safe to store NetworkTables keys in.
     */
 	this.create_map = function() {
-		return new d3_map();
+		return new Map();
 	};
 
 	/**
@@ -80,7 +41,7 @@ var NetworkTables = new function () {
     	:returns: Escaped value
     */
 	this.keySelector = function(str) {
-	    return encodeURIComponent(str).replace(/([;&,\.\+\*\~':"\!\^#$%@\[\]\(\)=>\|])/g, '\\$1');
+	    return encodeURIComponent(str).replace(/([;&,.+*~':"!^#$%@\[\]()=>|])/g, '\\$1');
 	};
 
 	//
@@ -89,17 +50,17 @@ var NetworkTables = new function () {
 
 
 	// functions that listen for connection changes
-	var connectionListeners = [];
-	var robotConnectionListeners = [];
+	const connectionListeners = new Set();
+	const robotConnectionListeners = new Set();
 
 	// functions that listen for everything
-	var globalListeners = [];
+	const globalListeners = new Set();
 
 	// functions that listen for specific keys
-	var keyListeners = new d3_map();
+	const keyListeners = new Map();
 
 	// contents of everything in NetworkTables that we know about
-	var ntCache = new d3_map();
+	let ntCache = new Map();
 
 	//
 	// NetworkTables JS API
@@ -115,18 +76,13 @@ var NetworkTables = new function () {
 	 	:returns: a function that will unsubscribe
     */
 	this.addWsConnectionListener = function(f, immediateNotify) {
-		connectionListeners.push(f);
+		connectionListeners.add(f);
 
-		if (immediateNotify == true) {
+		if (immediateNotify === true) {
 			f(socketOpen);
 		}
 
-		return function() {
-			const index = connectionListeners.indexOf(f);
-			if (index !== -1) {
-				connectionListeners.splice(index, 1);
-			}
-		}
+		return () => connectionListeners.delete(f);
 	};
 
 	/**
@@ -141,19 +97,14 @@ var NetworkTables = new function () {
 	 	:returns: a function that will unsubscribe
 	*/
 	this.addRobotConnectionListener = function(f, immediateNotify) {
-		robotConnectionListeners.push(f);
+		robotConnectionListeners.add(f);
 
-		if (immediateNotify == true) {
+		if (immediateNotify === true) {
 			f(robotConnected);
 		}
 
-		return function() {
-			const index = robotConnectionListeners.indexOf(f);
-			if (index !== -1) {
-				robotConnectionListeners.splice(index, 1);
-			}
-		}
-	}
+		return () => robotConnectionListeners.delete(f);
+	};
 
 	/**
 		Set a function that will be called whenever any NetworkTables value is changed
@@ -165,20 +116,15 @@ var NetworkTables = new function () {
 	 	:returns: a function that will unsubscribe
     */
 	this.addGlobalListener = function(f, immediateNotify) {
-		globalListeners.push(f);
+		globalListeners.add(f);
 
-		if (immediateNotify == true) {
+		if (immediateNotify === true) {
 			ntCache.forEach(function(k, v){
 				f(k, v, true);
 			});
 		}
 
-		return function() {
-			const index = globalListeners.indexOf(f);
-			if (index !== -1) {
-				globalListeners.splice(index, 1);
-			}
-		}
+		return () => globalListeners.delete(f);
 	};
 
 	/**
@@ -192,26 +138,21 @@ var NetworkTables = new function () {
 	 	:returns: a function that will unsubscribe
 	*/
 	this.addKeyListener = function(key, f, immediateNotify) {
-		var listeners = keyListeners.get(key);
+		const listeners = keyListeners.get(key);
 		if (listeners === undefined) {
-			keyListeners.set(key, [f]);
+			keyListeners.set(key, new Set([f]));
 		} else {
-			listeners.push(f);
+			listeners.add(f);
 		}
 
-		if (immediateNotify == true) {
-			var v = ntCache.get(key);
+		if (immediateNotify === true) {
+			const v = ntCache.get(key);
 			if (v !== undefined) {
 				f(key, v, true);
 			}
 		}
 
-		return function() {
-			const index = keyListeners.get(key).indexOf(f);
-			if (index !== -1) {
-				keyListeners.get(key).splice(index, 1);
-			}
-		}
+		return () => keyListeners.get(key).delete(f);
 	};
 
 	/**
@@ -231,7 +172,7 @@ var NetworkTables = new function () {
                  	 connected
     */
 	this.getKeys = function() {
-		return ntCache.getKeys();
+		return ntCache.keys();
 	};
 
 	/**
@@ -251,7 +192,7 @@ var NetworkTables = new function () {
 	              for changes to values, instead of using this function.
     */
 	this.getValue = function(key, defaultValue) {
-		var val = ntCache.get(key);
+		const val = ntCache.get(key);
 		if (val === undefined)
 			return defaultValue;
 		else
@@ -313,108 +254,77 @@ var NetworkTables = new function () {
 
 	// backwards compatibility; deprecated
 	this.setValue = this.putValue;
-	
-	//
-	// NetworkTables socket code
-	//
-	
-	var socket;
-	var socketOpen = false;
-	var robotConnected = false;
-	var robotAddress = null;
-	
+	socketOpen = false;
+	robotConnected = false;
+	robotAddress = null;
+
 	// construct the websocket URI
-	var loc = window.location;
-	var host;
-	
-	if (loc.protocol === "https:") {
-		host = "wss:";
-	} else {
-		host = "ws:";
-	}
-	
+	const loc = window.location;
+	const protocol = loc.protocol === "https:" ? "wss:" : "ws:";
 	// If the websocket is being served from a different host allow users 
 	// to add a data-nt-host="" attribute to the script tag loading 
 	// Networktables.
-	var ntHostElement = document.querySelector('[data-nt-host]');
-	if (ntHostElement) {
-		var ntHost = ntHostElement.getAttribute('data-nt-host');
-		host += "//" + ntHost;
-	} else {
-		host += "//" + loc.host;
-	}
-
-	host += "/networktables/ws";
+	const ntHostElement = document.querySelector('[data-nt-host]');
+	const host = ntHostElement ? ntHostElement.getAttribute('data-nt-host') : loc.host;
+	const address = `${protocol}//${host}/networktables/ws`;
 
 	function createSocket() {
 
-		socket = new WebSocket(host);
+		socket = new WebSocket(address);
 		if (socket) {
 
 			socket.onopen = function() {
-				console.log("Socket opened");
+				console.info("Socket opened");
 
 				socketOpen = true;
-				
-				for (var i in connectionListeners) {
-					connectionListeners[i](true);
-				}
+
+				connectionListeners.forEach(f => f(true));
 			};
 
 			socket.onmessage = function(msg) {
-				var data = JSON.parse(msg.data);
-				
+				const data = JSON.parse(msg.data);
+
 				// robot connection event
 				if (data.r !== undefined) {
 					robotConnected = data.r;
 					robotAddress = data.a;
-					for (var i in robotConnectionListeners) {
-						robotConnectionListeners[i](robotConnected);
-					}
+					robotConnectionListeners.forEach(f => f(robotConnected))
 				} else {
 
 					// data changed on websocket
-					var key = data['k'];
-					var value = data['v'];
-					var isNew = data['n'];
-					
+					const key = data['k'];
+					const value = data['v'];
+					const isNew = data['n'];
+
 					ntCache.set(key, value);
 
 					// notify global listeners
-					for (var i in globalListeners) {
-						globalListeners[i](key, value, isNew);
-					}
+					globalListeners.forEach(f => f(key, value, isNew));
 
 					// notify key-specific listeners
-					var listeners = keyListeners.get(key);
+					const listeners = keyListeners.get(key);
 					if (listeners !== undefined) {
-						for (var i in listeners) {
-							listeners[i](key, value, isNew);
-						}
+						listeners.forEach(f => f(key, value, isNew));
 					}
 				}
 			};
 
 			socket.onclose = function() {
 
 				if (socketOpen) {
-				
-					for (var i in connectionListeners) {
-						connectionListeners[i](false);
-					}
-					
-					for (var i in robotConnectionListeners) {
-						robotConnectionListeners[i](false);
-					}
+
+					connectionListeners.forEach(f => f(false));
+
+					robotConnectionListeners.forEach(f => f(false));
 
 					// clear ntCache, it's no longer valid
 					// TODO: Is this true?
-					ntCache = new d3_map();
+					ntCache = new Map();
 
 					socketOpen = false;
 					robotConnected = false;
 					robotAddress = null;
-					console.log("Socket closed");
+					console.info("Socket closed");
 				}
 
 				// respawn the websocket
@@ -424,6 +334,6 @@ var NetworkTables = new function () {
 	}
 
 	createSocket();
-}
+};