From 49398f5374bd064f90eab4ad6314b550e42a1e3e Mon Sep 17 00:00:00 2001
From: zadam <zadam.apps@gmail.com>
Date: Sat, 29 Feb 2020 19:43:19 +0100
Subject: [PATCH] refactoring of component event system + little docs

---
 .../javascripts/services/app_context.js       | 16 ++---
 src/public/javascripts/widgets/component.js   | 62 ++++++++++---------
 src/public/javascripts/widgets/note_info.js   |  2 +-
 .../javascripts/widgets/tab_caching_widget.js |  8 ++-
 4 files changed, 47 insertions(+), 41 deletions(-)

diff --git a/src/public/javascripts/services/app_context.js b/src/public/javascripts/services/app_context.js
index f0cd5b2d1..f759a60f4 100644
--- a/src/public/javascripts/services/app_context.js
+++ b/src/public/javascripts/services/app_context.js
@@ -65,22 +65,24 @@ class AppContext extends Component {
         this.triggerEvent('initialRenderComplete');
     }
 
-    async triggerEvent(name, data) {
-        await this.handleEvent(name, data);
+    /** @return {Promise} */
+    triggerEvent(name, data) {
+        return this.handleEvent(name, data);
     }
 
-    async triggerCommand(name, data = {}) {
+    /** @return {Promise} */
+    triggerCommand(name, data = {}) {
         for (const executor of this.executors) {
-            const called = await executor.handleCommand(name, data);
+            const fun = executor[name + "Command"];
 
-            if (called) {
-                return;
+            if (fun) {
+                return executor.callMethod(fun, data);
             }
         }
 
         console.debug(`Unhandled command ${name}, converting to event.`);
 
-        await this.triggerEvent(name, data);
+        return this.triggerEvent(name, data);
     }
 
     getComponentByEl(el) {
diff --git a/src/public/javascripts/widgets/component.js b/src/public/javascripts/widgets/component.js
index de1f70bee..f951ce8c1 100644
--- a/src/public/javascripts/widgets/component.js
+++ b/src/public/javascripts/widgets/component.js
@@ -1,6 +1,18 @@
 import utils from '../services/utils.js';
 import Mutex from "../services/mutex.js";
 
+/**
+ * Abstract class for all components in the Trilium's frontend.
+ *
+ * Contains also event implementation with following properties:
+ * - event / command distribution is synchronous which among others mean that events are well ordered - event
+ *   which was sent out first will also be processed first by the component since it was added to the mutex queue
+ *   as the first one
+ * - execution of the event / command is asynchronous - each component executes the event on its own without regard for
+ *   other components.
+ * - although the execution is async, we are collecting all the promises and therefore it is possible to wait until the
+ *   event / command is executed in all components - by simply awaiting the `triggerEvent()`.
+ */
 export default class Component {
     constructor() {
         this.componentId = `comp-${this.constructor.name}-` + utils.randomString(6);
@@ -24,50 +36,40 @@ export default class Component {
         return this;
     }
 
-    async handleEvent(name, data) {
-        await this.initialized;
-
-        const fun = this[name + 'Event'];
-
-        const start = Date.now();
-
-        await this.callMethod(fun, data);
-
-        const end = Date.now();
-
-        if (end - start > 10 && glob.PROFILING_LOG) {
-            console.log(`Event ${name} in component ${this.componentId} took ${end-start}ms`);
-        }
-
-        await this.handleEventInChildren(name, data);
+    /** @return {Promise} */
+    handleEvent(name, data) {
+        return Promise.all([
+            this.initialized.then(() => this.callMethod(this[name + 'Event'], data)),
+            this.handleEventInChildren(name, data)
+        ]);
     }
 
-    async triggerEvent(name, data) {
-        await this.parent.triggerEvent(name, data);
+    /** @return {Promise} */
+    triggerEvent(name, data) {
+        return this.parent.triggerEvent(name, data);
     }
 
-    async handleEventInChildren(name, data) {
+    /** @return {Promise} */
+    handleEventInChildren(name, data) {
         const promises = [];
 
         for (const child of this.children) {
             promises.push(child.handleEvent(name, data));
         }
 
-        await Promise.all(promises);
+        return Promise.all(promises);
     }
 
-    async triggerCommand(name, data = {}) {
-        const called = await this.handleCommand(name, data);
-
-        if (!called) {
-            await this.parent.triggerCommand(name, data);
-        }
-    }
-
-    async handleCommand(name, data) {
+    /** @return {Promise} */
+    triggerCommand(name, data = {}) {
         const fun = this[name + 'Command'];
 
-        return await this.callMethod(fun, data);
+        if (fun) {
+            return this.callMethod(fun, data);
+        }
+        else {
+            return this.parent.triggerCommand(name, data);
+        }
     }
 
     async callMethod(fun, data) {
diff --git a/src/public/javascripts/widgets/note_info.js b/src/public/javascripts/widgets/note_info.js
index 7eac5f9ff..cf0fa5dd0 100644
--- a/src/public/javascripts/widgets/note_info.js
+++ b/src/public/javascripts/widgets/note_info.js
@@ -38,7 +38,7 @@ const TPL = `
 export default class NoteInfoWidget extends CollapsibleWidget {
     getWidgetTitle() { return "Note info"; }
 
-    doRenderBody() {
+    async doRenderBody() {
         this.$body.html(TPL);
 
         this.$noteId = this.$body.find(".note-info-note-id");
diff --git a/src/public/javascripts/widgets/tab_caching_widget.js b/src/public/javascripts/widgets/tab_caching_widget.js
index 9731bf9f8..3fe808c90 100644
--- a/src/public/javascripts/widgets/tab_caching_widget.js
+++ b/src/public/javascripts/widgets/tab_caching_widget.js
@@ -17,15 +17,17 @@ export default class TabCachingWidget extends TabAwareWidget {
         return this.$widget = $(`<div class="marker" style="display: none;">`);
     }
 
-    async handleEventInChildren(name, data) {
+    handleEventInChildren(name, data) {
         // stop propagation of the event to the children, individual tab widget should not know about tab switching
         // since they are per-tab
         if (name === 'tabNoteSwitchedAndActivated') {
-            await super.handleEventInChildren('tabNoteSwitched', data);
+            return super.handleEventInChildren('tabNoteSwitched', data);
         }
         else if (name !== 'activeTabChanged') {
-            await super.handleEventInChildren(name, data);
+            return super.handleEventInChildren(name, data);
         }
+
+        return Promise.resolve();
     }
 
     async newTabOpenedEvent({tabId}) {