fix(webpack): use async type-checking in watch mode

packages/webpack5/src/configuration/angular.ts

@@ -186,7 +186,7 @@ export default function (config: Config, env: IWebpackEnv = _env): Config {
 				paths.indexOf('@nativescript/core/globals/index.js')
 			] = polyfillsPath;
 
-			// replace paths with the update paths
+			// replace paths with the updated paths
 			config.entry('bundle').clear().merge(paths);
 		}
 	}

packages/webpack5/src/configuration/base.ts

@@ -233,11 +233,7 @@ export default function (config: Config, env: IWebpackEnv = _env): Config {
 			.plugin('ForkTsCheckerWebpackPlugin')
 			.use(ForkTsCheckerWebpackPlugin, [
 				{
-					// If we use "async" errors compiling typescript will be ignored by
-					// WebPack (we will send the "compilation" message back to the CLI,
-					// and the process exit code will be zero), therefore we will end
-					// up with a broken build
-					async: false,
+					async: !!env.watch,
 					typescript: {
 						memoryLimit: 4096,
 					},