extensions/typescript-language-features/src/ui/jsNodeWalkthrough.electron.ts/createNewJSFile
async function createNewJSFile(walkthroughState: JsWalkthroughState) {
	const newFile = await vscode.workspace.openTextDocument({
		language: 'javascript',
		content: `// Write a message to the console.\nconsole.log('hello world!');\n`,
	});
	walkthroughState.exampleJsDocument = newFile;
	return vscode.window.showTextDocument(newFile, vscode.ViewColumn.Beside);
}