Was able to dispose of the webview resources properly. We are able to…

src/extension.ts

@@ -1,37 +1,67 @@
 import * as vscode from 'vscode';
 import {createPanel} from './panel';
 import { Parser } from './parser';
+import { Tree } from './types/tree';
+
+let tree: Parser | undefined = undefined;
+let panel: vscode.WebviewPanel | undefined = undefined
+
 
 // This method is called when your extension is activated
 // Your extension is activated the very first time the command is executed
-
 function activate(context: vscode.ExtensionContext) {
 
-	let disposable = vscode.commands.registerCommand('react-labyrinth.helloWorld', function () {
-		vscode.window.showInformationMessage('Hello World from React Labyrinth!');
-	});
+	// This is the column where Webview will be revealed to
+	const columnToShowIn : vscode.ViewColumn | undefined = vscode.window.activeTextEditor
+        ? vscode.window.activeTextEditor.viewColumn
+        : undefined;
+
+
+	// Command that allows for User to select the root file of their React application.
+	const pickFile: vscode.Disposable = vscode.commands.registerCommand('myExtension.pickFile', async () => {
+
 
-	// pass in the command we want to register (refer to package.json)
-	// let result = vscode.commands.registerCommand('myExtension.showPanel', () => {
-	// 	// call helper func
-	// 	createPanel(context);
-	// });
+		// Check if there is an existing webview panel, if so display it.
+		if(panel) {
+			panel.reveal(columnToShowIn)
+		}
 
-	vscode.commands.registerCommand('myExtension.pickFile', async () => {
-		const fileArray = await vscode.window.showOpenDialog({ canSelectFolders: false, canSelectFiles: true, canSelectMany: false });
+
+		// Opens window for the User to select the root file of React application
+		const fileArray: vscode.Uri[] = await vscode.window.showOpenDialog({ canSelectFolders: false, canSelectFiles: true, canSelectMany: false });
 
+
+		// Throw error message if no file was selected
 		if (!fileArray || fileArray.length === 0) {
 			vscode.window.showErrorMessage('No file selected');
 			return;
 		}
-
-		const tree = new Parser(fileArray[0].path);
+
+
+		// Create Tree to be inserted into returned HTML
+		tree = new Parser(fileArray[0].path);
 		tree.parse();
-		const data = tree.getTree();
-		console.log('Data sent back: \n', data);
-		createPanel(context, data);
+		const data: Tree = tree.getTree();
+
+
+		// Check if panel currently has a webview, if it does dispose of it and create another with updated root file selected. 
+		// Otherwise create a new webview to display root file selected.
+		if(!panel) {
+			panel = createPanel(context, data, columnToShowIn);
+		} else {
+			panel.dispose()
+			panel = createPanel(context, data, columnToShowIn);
+		}
 	});
-	context.subscriptions.push(disposable);
+
+
+	// Command to show panel if it is hidden
+	const showPanel: vscode.Disposable = vscode.commands.registerCommand('myExtension.showPanel', () => {
+		panel.reveal(columnToShowIn)
+	  });
+
+
+	context.subscriptions.push(pickFile, showPanel);
 }
 
 // This method is called when your extension is deactivated

src/panel.ts

@@ -2,40 +2,58 @@ import * as vscode from 'vscode';
 import { getNonce } from './getNonce';
 import { Tree } from './types/tree';
 
-export function createPanel(context: vscode.ExtensionContext, data: Tree) {
-    // if the current panel exists, then reveal the column, else make one?
+let panel: vscode.WebviewPanel | undefined = undefined
+
+export function createPanel(context: vscode.ExtensionContext, data: Tree, columnToShowIn: vscode.ViewColumn) {
 
     // utilize method on vscode.window object to create webview
-    const panel = vscode.window.createWebviewPanel(
+    panel = vscode.window.createWebviewPanel(
         'reactLabyrinth',
         'React Labyrinth',
+
         // create one new tab
         vscode.ViewColumn.One,
         {
             enableScripts: true,
             retainContextWhenHidden: true
         }
     );
+
 
+    // Set the icon logo of extension webview
     panel.iconPath = vscode.Uri.joinPath(context.extensionUri, 'media', 'favicon.ico');
+
+
+    // Set URI to be the path to bundle
+    const bundlePath: vscode.Uri = vscode.Uri.joinPath(context.extensionUri, 'build', 'bundle.js');
 
-    const bundlePath = vscode.Uri.joinPath(context.extensionUri, 'build', 'bundle.js');
 
     // set webview URI to pass into html script
-    const bundleURI = panel.webview.asWebviewUri(bundlePath);
+    const bundleURI: vscode.Uri = panel.webview.asWebviewUri(bundlePath);
+
 
     // render html of webview here
     panel.webview.html = createWebviewHTML(bundleURI, data);
 
-    // will need to use onDidDispose to clear cached data and reset tree when the webview and/or application is closed
 
+    // Listens for when webview is closed and disposes of webview resources
+    panel.onDidDispose(
+        () => {
+          panel = undefined;
+        },
+        null,
+        context.subscriptions
+      );
+
+
+    // Sends data to Flow.tsx to be displayed after parsed data is received
     panel.webview.onDidReceiveMessage(
         async (msg: any) => {
             switch (msg.type) {
                 case 'onData':
                     if (!msg.value) break;
                     context.workspaceState.update('reactLabyrinth', msg.value);
-                    // console.log('msg.value from panel.js: ', msg.value);
+
                     panel.webview.postMessage(
                         {
                             type: 'parsed-data',
@@ -49,13 +67,18 @@ export function createPanel(context: vscode.ExtensionContext, data: Tree) {
         undefined,
         context.subscriptions
     );
+
+    return panel
 };
 
+
+
 // getNonce generates a new random string each time ext is used to prevent external injection of foreign code into the html 
-const nonce = getNonce();
+const nonce: string = getNonce();
+
 
 // function to create the HTML page for webview
-function createWebviewHTML(URI: vscode.Uri, initialData: Tree) {
+function createWebviewHTML(URI: vscode.Uri, initialData: Tree) : string {
     return (
         `
             <!DOCTYPE html>