fix: Use View Engine LS for projects < v9

`ngcc` does not work correctly for Angular projects < version 9, so
automatically switch to View Engine LS when such projects are detected in
the workspace.

Author: kyliau

client/src/client.ts

@@ -14,6 +14,7 @@ import * as lsp from 'vscode-languageclient/node';
 import {ProjectLoadingFinish, ProjectLoadingStart, SuggestStrictMode, SuggestStrictModeParams} from '../common/notifications';
 import {NgccProgress, NgccProgressToken, NgccProgressType} from '../common/progress';
 import {GetComponentsWithTemplateFile, GetTcbRequest, IsInAngularProject} from '../common/requests';
+import {resolve, Version} from '../common/resolver';
 
 import {isInsideComponentDecorator, isInsideInlineTemplateRegion} from './embedded_support';
 import {ProgressReporter} from './progress-reporter';
@@ -388,7 +389,7 @@ function constructArgs(ctx: vscode.ExtensionContext): string[] {
   const ngProbeLocations = getProbeLocations(ngdk, ctx.extensionPath);
   args.push('--ngProbeLocations', ngProbeLocations.join(','));
 
-  const viewEngine: boolean = config.get('angular.view-engine', false);
+  const viewEngine: boolean = config.get('angular.view-engine', !allProjectsSupportIvy());
   if (viewEngine) {
     args.push('--viewEngine');
   }
@@ -432,4 +433,19 @@ function getServerOptions(ctx: vscode.ExtensionContext, debug: boolean): lsp.Nod
       execArgv: debug ? devExecArgv : prodExecArgv,
     },
   };
-}
+}
+
+/**
+ * Returns true if all projects in the workspace support Ivy LS, otherwise
+ * return false.
+ */
+function allProjectsSupportIvy() {
+  const workspaceFolders = vscode.workspace.workspaceFolders || [];
+  for (const workspaceFolder of workspaceFolders) {
+    const angularCore = resolve('@angular/core', workspaceFolder.uri.fsPath);
+    if (angularCore?.version.greaterThanOrEqual(new Version('9')) === false) {
+      return false;
+    }
+  }
+  return true;
+}