From f0253075d850f77fc05daeb454afe8984e31af87 Mon Sep 17 00:00:00 2001
From: Pavel Djundik <xPaw@users.noreply.github.com>
Date: Mon, 16 Mar 2020 19:58:40 +0200
Subject: [PATCH] Create an event bus

---
 client/components/App.vue            |  7 +++--
 client/components/ChannelWrapper.vue |  3 +-
 client/components/Chat.vue           |  5 ++--
 client/components/ChatInput.vue      |  5 ++--
 client/components/ConfirmDialog.vue  | 10 ++++---
 client/components/ContextMenu.vue    | 13 +++++----
 client/components/DateMarker.vue     |  7 +++--
 client/components/ImageViewer.vue    |  9 +++---
 client/components/LinkPreview.vue    |  5 ++--
 client/components/Mentions.vue       |  5 ++--
 client/components/MessageList.vue    |  5 ++--
 client/components/Username.vue       |  3 +-
 client/js/eventbus.js                | 43 ++++++++++++++++++++++++++++
 client/js/helpers/contextMenu.js     |  3 +-
 client/js/vue.js                     |  9 +++---
 15 files changed, 95 insertions(+), 37 deletions(-)
 create mode 100644 client/js/eventbus.js

diff --git a/client/components/App.vue b/client/components/App.vue
index b4e8c023..b136874f 100644
--- a/client/components/App.vue
+++ b/client/components/App.vue
@@ -13,6 +13,7 @@
 
 <script>
 const constants = require("../js/constants");
+import eventbus from "../js/eventbus";
 import Mousetrap from "mousetrap";
 import throttle from "lodash/throttle";
 import storage from "../js/localStorage";
@@ -53,14 +54,14 @@ export default {
 
 		// Make a single throttled resize listener available to all components
 		this.debouncedResize = throttle(() => {
-			this.$root.$emit("resize");
+			eventbus.emit("resize");
 		}, 100);
 
 		window.addEventListener("resize", this.debouncedResize, {passive: true});
 
 		// Emit a daychange event every time the day changes so date markers know when to update themselves
 		const emitDayChange = () => {
-			this.$root.$emit("daychange");
+			eventbus.emit("daychange");
 			// This should always be 24h later but re-computing exact value just in case
 			this.dayChangeTimeout = setTimeout(emitDayChange, this.msUntilNextDay());
 		};
@@ -77,7 +78,7 @@ export default {
 	},
 	methods: {
 		escapeKey() {
-			this.$root.$emit("escapekey");
+			eventbus.emit("escapekey");
 		},
 		toggleSidebar(e) {
 			if (isIgnoredKeybind(e)) {
diff --git a/client/components/ChannelWrapper.vue b/client/components/ChannelWrapper.vue
index 25b77ccf..c979007f 100644
--- a/client/components/ChannelWrapper.vue
+++ b/client/components/ChannelWrapper.vue
@@ -30,6 +30,7 @@
 </template>
 
 <script>
+import eventbus from "../js/eventbus";
 import isChannelCollapsed from "../js/helpers/isChannelCollapsed";
 
 export default {
@@ -74,7 +75,7 @@ export default {
 			this.$root.switchToChannel(this.channel);
 		},
 		openContextMenu(event) {
-			this.$root.$emit("contextmenu:channel", {
+			eventbus.emit("contextmenu:channel", {
 				event: event,
 				channel: this.channel,
 				network: this.network,
diff --git a/client/components/Chat.vue b/client/components/Chat.vue
index f4b55a6a..8c91d100 100644
--- a/client/components/Chat.vue
+++ b/client/components/Chat.vue
@@ -102,6 +102,7 @@
 
 <script>
 import socket from "../js/socket";
+import eventbus from "../js/eventbus";
 import ParsedMessage from "./ParsedMessage.vue";
 import MessageList from "./MessageList.vue";
 import ChatInput from "./ChatInput.vue";
@@ -197,14 +198,14 @@ export default {
 			}
 		},
 		openContextMenu(event) {
-			this.$root.$emit("contextmenu:channel", {
+			eventbus.emit("contextmenu:channel", {
 				event: event,
 				channel: this.channel,
 				network: this.network,
 			});
 		},
 		openMentions() {
-			this.$root.$emit("mentions:toggle", {
+			eventbus.emit("mentions:toggle", {
 				event: event,
 			});
 		},
diff --git a/client/components/ChatInput.vue b/client/components/ChatInput.vue
index c007d12e..a384b2ec 100644
--- a/client/components/ChatInput.vue
+++ b/client/components/ChatInput.vue
@@ -56,6 +56,7 @@ import autocompletion from "../js/autocompletion";
 import commands from "../js/commands/index";
 import socket from "../js/socket";
 import upload from "../js/upload";
+import eventbus from "../js/eventbus";
 
 const formattingHotkeys = {
 	"mod+k": "\x03",
@@ -101,7 +102,7 @@ export default {
 		},
 	},
 	mounted() {
-		this.$root.$on("escapekey", this.blurInput);
+		eventbus.on("escapekey", this.blurInput);
 
 		if (this.$store.state.settings.autocomplete) {
 			autocompletionRef = autocompletion(this.$refs.input);
@@ -163,7 +164,7 @@ export default {
 		}
 	},
 	destroyed() {
-		this.$root.$off("escapekey", this.blurInput);
+		eventbus.off("escapekey", this.blurInput);
 
 		if (autocompletionRef) {
 			autocompletionRef.destroy();
diff --git a/client/components/ConfirmDialog.vue b/client/components/ConfirmDialog.vue
index c7ca473c..af92e368 100644
--- a/client/components/ConfirmDialog.vue
+++ b/client/components/ConfirmDialog.vue
@@ -51,6 +51,8 @@
 </style>
 
 <script>
+import eventbus from "../js/eventbus";
+
 export default {
 	name: "ConfirmDialog",
 	data() {
@@ -60,12 +62,12 @@ export default {
 		};
 	},
 	mounted() {
-		this.$root.$on("escapekey", this.close);
-		this.$root.$on("confirm-dialog", this.open);
+		eventbus.on("escapekey", this.close);
+		eventbus.on("confirm-dialog", this.open);
 	},
 	destroyed() {
-		this.$root.$off("escapekey", this.close);
-		this.$root.$off("confirm-dialog", this.open);
+		eventbus.off("escapekey", this.close);
+		eventbus.off("confirm-dialog", this.open);
 	},
 	methods: {
 		open(data, callback) {
diff --git a/client/components/ContextMenu.vue b/client/components/ContextMenu.vue
index a1cfefc2..73c7e79a 100644
--- a/client/components/ContextMenu.vue
+++ b/client/components/ContextMenu.vue
@@ -39,6 +39,7 @@
 
 <script>
 import {generateUserContextMenu, generateChannelContextMenu} from "../js/helpers/contextMenu.js";
+import eventbus from "../js/eventbus";
 
 export default {
 	name: "ContextMenu",
@@ -58,14 +59,14 @@ export default {
 		};
 	},
 	mounted() {
-		this.$root.$on("escapekey", this.close);
-		this.$root.$on("contextmenu:user", this.openUserContextMenu);
-		this.$root.$on("contextmenu:channel", this.openChannelContextMenu);
+		eventbus.on("escapekey", this.close);
+		eventbus.on("contextmenu:user", this.openUserContextMenu);
+		eventbus.on("contextmenu:channel", this.openChannelContextMenu);
 	},
 	destroyed() {
-		this.$root.$off("escapekey", this.close);
-		this.$root.$off("contextmenu:user", this.openUserContextMenu);
-		this.$root.$off("contextmenu:channel", this.openChannelContextMenu);
+		eventbus.off("escapekey", this.close);
+		eventbus.off("contextmenu:user", this.openUserContextMenu);
+		eventbus.off("contextmenu:channel", this.openChannelContextMenu);
 
 		this.close();
 	},
diff --git a/client/components/DateMarker.vue b/client/components/DateMarker.vue
index eacef30f..c8cf5468 100644
--- a/client/components/DateMarker.vue
+++ b/client/components/DateMarker.vue
@@ -9,6 +9,7 @@
 <script>
 import dayjs from "dayjs";
 import calendar from "dayjs/plugin/calendar";
+import eventbus from "../js/eventbus";
 
 dayjs.extend(calendar);
 
@@ -24,11 +25,11 @@ export default {
 	},
 	mounted() {
 		if (this.hoursPassed() < 48) {
-			this.$root.$on("daychange", this.dayChange);
+			eventbus.on("daychange", this.dayChange);
 		}
 	},
 	beforeDestroy() {
-		this.$root.$off("daychange", this.dayChange);
+		eventbus.off("daychange", this.dayChange);
 	},
 	methods: {
 		hoursPassed() {
@@ -38,7 +39,7 @@ export default {
 			this.$forceUpdate();
 
 			if (this.hoursPassed() >= 48) {
-				this.$root.$off("daychange", this.dayChange);
+				eventbus.off("daychange", this.dayChange);
 			}
 		},
 		friendlyDate() {
diff --git a/client/components/ImageViewer.vue b/client/components/ImageViewer.vue
index 4aa1aa84..8ad19773 100644
--- a/client/components/ImageViewer.vue
+++ b/client/components/ImageViewer.vue
@@ -40,6 +40,7 @@
 
 <script>
 import Mousetrap from "mousetrap";
+import eventbus from "../js/eventbus";
 
 export default {
 	name: "ImageViewer",
@@ -79,8 +80,8 @@ export default {
 		link(newLink, oldLink) {
 			// TODO: history.pushState
 			if (newLink === null) {
-				this.$root.$off("escapekey", this.closeViewer);
-				this.$root.$off("resize", this.correctPosition);
+				eventbus.off("escapekey", this.closeViewer);
+				eventbus.off("resize", this.correctPosition);
 				Mousetrap.unbind("left", this.previous);
 				Mousetrap.unbind("right", this.next);
 				return;
@@ -89,8 +90,8 @@ export default {
 			this.setPrevNextImages();
 
 			if (!oldLink) {
-				this.$root.$on("escapekey", this.closeViewer);
-				this.$root.$on("resize", this.correctPosition);
+				eventbus.on("escapekey", this.closeViewer);
+				eventbus.on("resize", this.correctPosition);
 				Mousetrap.bind("left", this.previous);
 				Mousetrap.bind("right", this.next);
 			}
diff --git a/client/components/LinkPreview.vue b/client/components/LinkPreview.vue
index 9ccce2e3..9ae10b74 100644
--- a/client/components/LinkPreview.vue
+++ b/client/components/LinkPreview.vue
@@ -130,6 +130,7 @@
 </template>
 
 <script>
+import eventbus from "../js/eventbus";
 import friendlysize from "../js/helpers/friendlysize";
 
 export default {
@@ -167,12 +168,12 @@ export default {
 		this.updateShownState();
 	},
 	mounted() {
-		this.$root.$on("resize", this.handleResize);
+		eventbus.on("resize", this.handleResize);
 
 		this.onPreviewUpdate();
 	},
 	beforeDestroy() {
-		this.$root.$off("resize", this.handleResize);
+		eventbus.off("resize", this.handleResize);
 	},
 	destroyed() {
 		// Let this preview go through load/canplay events again,
diff --git a/client/components/Mentions.vue b/client/components/Mentions.vue
index 4147492c..683ca3db 100644
--- a/client/components/Mentions.vue
+++ b/client/components/Mentions.vue
@@ -125,6 +125,7 @@
 import Username from "./Username.vue";
 import ParsedMessage from "./ParsedMessage.vue";
 import socket from "../js/socket";
+import eventbus from "../js/eventbus";
 import localetime from "../js/helpers/localetime";
 import dayjs from "dayjs";
 import relativeTime from "dayjs/plugin/relativeTime";
@@ -161,10 +162,10 @@ export default {
 		},
 	},
 	mounted() {
-		this.$root.$on("mentions:toggle", this.openPopup);
+		eventbus.on("mentions:toggle", this.openPopup);
 	},
 	destroyed() {
-		this.$root.$off("mentions:toggle", this.openPopup);
+		eventbus.off("mentions:toggle", this.openPopup);
 	},
 	methods: {
 		messageTime(time) {
diff --git a/client/components/MessageList.vue b/client/components/MessageList.vue
index 0a405255..1e3e9128 100644
--- a/client/components/MessageList.vue
+++ b/client/components/MessageList.vue
@@ -56,6 +56,7 @@
 
 <script>
 const constants = require("../js/constants");
+import eventbus from "../js/eventbus";
 import clipboard from "../js/clipboard";
 import socket from "../js/socket";
 import Message from "./Message.vue";
@@ -173,7 +174,7 @@ export default {
 	mounted() {
 		this.$refs.chat.addEventListener("scroll", this.handleScroll, {passive: true});
 
-		this.$root.$on("resize", this.handleResize);
+		eventbus.on("resize", this.handleResize);
 
 		this.$nextTick(() => {
 			if (this.historyObserver) {
@@ -185,7 +186,7 @@ export default {
 		this.unreadMarkerShown = false;
 	},
 	beforeDestroy() {
-		this.$root.$off("resize", this.handleResize);
+		eventbus.off("resize", this.handleResize);
 		this.$refs.chat.removeEventListener("scroll", this.handleScroll);
 	},
 	destroyed() {
diff --git a/client/components/Username.vue b/client/components/Username.vue
index a301da37..b3806922 100644
--- a/client/components/Username.vue
+++ b/client/components/Username.vue
@@ -11,6 +11,7 @@
 </template>
 
 <script>
+import eventbus from "../js/eventbus";
 import colorClass from "../js/helpers/colorClass";
 
 export default {
@@ -30,7 +31,7 @@ export default {
 			return this.onHover(this.user);
 		},
 		openContextMenu(event) {
-			this.$root.$emit("contextmenu:user", {
+			eventbus.emit("contextmenu:user", {
 				event: event,
 				user: this.user,
 			});
diff --git a/client/js/eventbus.js b/client/js/eventbus.js
new file mode 100644
index 00000000..8f66ae31
--- /dev/null
+++ b/client/js/eventbus.js
@@ -0,0 +1,43 @@
+const events = new Map();
+
+class EventBus {
+	/**
+	 * Register an event handler for the given type.
+	 *
+	 * @param  {String} type    Type of event to listen for.
+	 * @param  {Function} handler Function to call in response to given event.
+	 */
+	on(type, handler) {
+		if (events.has(type)) {
+			events[type].push(handler);
+		} else {
+			events[type] = [handler];
+		}
+	}
+
+	/**
+	 * Remove an event handler for the given type.
+	 *
+	 * @param  {String} type    Type of event to unregister `handler` from.
+	 * @param  {Function} handler Handler function to remove.
+	 */
+	off(type, handler) {
+		if (events.has(type)) {
+			events[type] = events[type].filter((item) => item !== handler);
+		}
+	}
+
+	/**
+	 * Invoke all handlers for the given type.
+	 *
+	 * @param {String} type  The event type to invoke.
+	 * @param {Any} [evt]  Any value (object is recommended and powerful), passed to each handler.
+	 */
+	emit(type, evt) {
+		if (events.has(type)) {
+			events[type].slice().map((handler) => handler(evt));
+		}
+	}
+}
+
+export default new EventBus();
diff --git a/client/js/helpers/contextMenu.js b/client/js/helpers/contextMenu.js
index 49b3834e..8496cfa2 100644
--- a/client/js/helpers/contextMenu.js
+++ b/client/js/helpers/contextMenu.js
@@ -1,6 +1,7 @@
 "use strict";
 
 import socket from "../socket";
+import eventbus from "../eventbus";
 
 export function generateChannelContextMenu($root, channel, network) {
 	const typeMap = {
@@ -135,7 +136,7 @@ export function generateChannelContextMenu($root, channel, network) {
 			type: "item",
 			class: "clear-history",
 			action() {
-				$root.$emit(
+				eventbus.emit(
 					"confirm-dialog",
 					{
 						title: "Clear history",
diff --git a/client/js/vue.js b/client/js/vue.js
index 3467b3c4..f561cae2 100644
--- a/client/js/vue.js
+++ b/client/js/vue.js
@@ -9,6 +9,7 @@ import App from "../components/App.vue";
 import storage from "./localStorage";
 import {router, navigate} from "./router";
 import socket from "./socket";
+import eventbus from "./eventbus";
 
 import "./socket-events";
 import "./webpush";
@@ -18,7 +19,7 @@ const favicon = document.getElementById("favicon");
 const faviconNormal = favicon.getAttribute("href");
 const faviconAlerted = favicon.dataset.other;
 
-const vueApp = new Vue({
+new Vue({
 	el: "#viewport",
 	router,
 	mounted() {
@@ -30,7 +31,7 @@ const vueApp = new Vue({
 		},
 		closeChannel(channel) {
 			if (channel.type === "lobby") {
-				this.$root.$emit(
+				eventbus.emit(
 					"confirm-dialog",
 					{
 						title: "Remove network",
@@ -75,7 +76,7 @@ store.watch(
 	(sidebarOpen) => {
 		if (window.innerWidth > constants.mobileViewportPixels) {
 			storage.set("thelounge.state.sidebar", sidebarOpen);
-			vueApp.$emit("resize");
+			eventbus.emit("resize");
 		}
 	}
 );
@@ -84,7 +85,7 @@ store.watch(
 	(state) => state.userlistOpen,
 	(userlistOpen) => {
 		storage.set("thelounge.state.userlist", userlistOpen);
-		vueApp.$emit("resize");
+		eventbus.emit("resize");
 	}
 );