Move tabs state out into React (#621)

This PR is just about moving the tabs array. I'm hoping to let it bake for a bit before merging the rest of the tabs in react work.

Preview here: https://ms.portal.azure.com/?dataExplorerSource=https%3A%2F%2Fcosmos-explorer-preview.azurewebsites.net%2Fcommit%2Fda809beb82bb54dc82da18eda41caaf7b9b6597f%2Fexplorer.html#@microsoft.onmicrosoft.com/resource/subscriptions/b9c77f10-b438-4c32-9819-eef8a654e478/resourceGroups/stfaul/providers/Microsoft.DocumentDb/databaseAccounts/stfaul-sql/dataExplorer

src/Explorer/Explorer.tsx

@@ -93,6 +93,7 @@ export interface ExplorerParams {
   closeSidePanel: () => void;
   closeDialog: () => void;
   openDialog: (props: DialogProps) => void;
+  tabsManager: TabsManager;
 }
 
 export default class Explorer {
@@ -600,7 +601,7 @@ export default class Explorer {
       container: this,
     });
 
-    this.tabsManager = new TabsManager();
+    this.tabsManager = params?.tabsManager ?? new TabsManager();
 
     this._panes = [
       this.addDatabasePane,

src/Explorer/SplashScreen/SplashScreen.tsx

@@ -50,10 +50,6 @@ export class SplashScreen extends React.Component<SplashScreenProps> {
     this.subscriptions = [];
   }
 
-  public shouldComponentUpdate() {
-    return this.container.tabsManager.openedTabs.length === 0;
-  }
-
   public componentWillUnmount() {
     while (this.subscriptions.length) {
       this.subscriptions.pop().dispose();
@@ -62,7 +58,6 @@ export class SplashScreen extends React.Component<SplashScreenProps> {
 
   public componentDidMount() {
     this.subscriptions.push(
-      this.container.tabsManager.openedTabs.subscribe(() => this.setState({})),
       this.container.selectedNode.subscribe(() => this.setState({})),
       this.container.isNotebookEnabled.subscribe(() => this.setState({}))
     );
@@ -80,7 +75,13 @@ export class SplashScreen extends React.Component<SplashScreenProps> {
     const tipsItems = this.createTipsItems();
     const onClearRecent = this.clearMostRecent;
 
-    return (
+    const formContainer = (jsx: JSX.Element) => (
+      <div className="connectExplorerContainer">
+        <form className="connectExplorerFormContainer">{jsx}</form>
+      </div>
+    );
+
+    return formContainer(
       <div className="splashScreenContainer">
         <div className="splashScreen">
           <div className="title">

src/Main.tsx

@@ -53,6 +53,7 @@ import "./Explorer/Tabs/QueryTab.less";
 import { useConfig } from "./hooks/useConfig";
 import { useKnockoutExplorer } from "./hooks/useKnockoutExplorer";
 import { useSidePanel } from "./hooks/useSidePanel";
+import { useTabs } from "./hooks/useTabs";
 import { KOCommentEnd, KOCommentIfStart } from "./koComment";
 import "./Libs/jquery";
 import "./Shared/appInsights";
@@ -78,6 +79,7 @@ const App: React.FunctionComponent = () => {
   };
 
   const { isPanelOpen, panelContent, headerText, openSidePanel, closeSidePanel } = useSidePanel();
+  const { tabs, tabsManager } = useTabs();
 
   const explorerParams: ExplorerParams = {
     setIsNotificationConsoleExpanded,
@@ -87,7 +89,9 @@ const App: React.FunctionComponent = () => {
     closeSidePanel,
     openDialog,
     closeDialog,
+    tabsManager,
   };
+
   const config = useConfig();
   const explorer = useKnockoutExplorer(config?.platform, explorerParams);
 
@@ -200,11 +204,7 @@ const App: React.FunctionComponent = () => {
             {/* Splitter - End */}
           </div>
           {/* Collections Tree - End */}
-          <div className="connectExplorerContainer" data-bind="visible: tabsManager.openedTabs().length === 0">
-            <form className="connectExplorerFormContainer">
-              <SplashScreen explorer={explorer} />
-            </form>
-          </div>
+          {tabs.length === 0 && <SplashScreen explorer={explorer} />}
           <div className="tabsManagerContainer" data-bind='component: { name: "tabs-manager", params: tabsManager }' />
         </div>
         {/* Collections Tree and Tabs - End */}

src/hooks/useObservableState.ts

@@ -0,0 +1,16 @@
+import { isObservableArray, Observable, ObservableArray } from "knockout";
+import { useEffect, useState } from "react";
+
+export function useObservableState<T>(observable: Observable<T>): [T, (s: T) => void];
+export function useObservableState<T>(observable: ObservableArray<T>): [T[], (s: T[]) => void];
+export function useObservableState<T>(observable: ObservableArray<T> | Observable<T>): [T | T[], (s: T | T[]) => void] {
+  const [value, setValue] = useState(observable());
+
+  useEffect(() => {
+    isObservableArray(observable)
+      ? observable.subscribe((values) => setValue([...values]))
+      : observable.subscribe(setValue);
+  }, [observable]);
+
+  return [value, observable];
+}

src/hooks/useTabs.ts

@@ -0,0 +1,16 @@
+import { useState } from "react";
+import TabsBase from "../Explorer/Tabs/TabsBase";
+import { TabsManager } from "../Explorer/Tabs/TabsManager";
+import { useObservableState } from "./useObservableState";
+
+export type UseTabs = {
+  tabs: readonly TabsBase[];
+  tabsManager: TabsManager;
+};
+
+export function useTabs(): UseTabs {
+  const [tabsManager] = useState(() => new TabsManager());
+  const [tabs] = useObservableState(tabsManager.openedTabs);
+
+  return { tabs, tabsManager };
+}