Async LanguageServiceHost

Search Terms

language, service, host, async, api

Suggestion

It'd super awesome if Language Service would accept a LanguageServiceHost with async API

Use Cases

Using LanguageService in environments where readFileSync is not available like browsers (using browserfs package or fs provided by WebSockets)

I'm working on an app like CodeSandbox but a bit more sophisticated.

Examples

class Host implements ts.LanguageServiceHost {
  async getScriptSnapshot(filename: string): Promise<ts.IScriptSnapshot> { }
  async readFile(filename: string): Promise<string> {}
}

Checklist

My suggestion meets these guidelines:

• This wouldn't be a breaking change in existing TypeScript/JavaScript code
• This wouldn't change the runtime behavior of existing JavaScript code
• This could be implemented without emitting different JS based on the types of the expressions
• This isn't a runtime feature (e.g. library functionality, non-ECMAScript syntax with JavaScript output, etc.)
• This feature would agree with the rest of TypeScript's Design Goals.

issue で説明されている LanguageServiceHost API と LanguageService API から始め、現在の同期的な前提を、非同期の getScriptSnapshot と readFile の例と比較します。readFileSync を利用できないブラウザー環境に必要な API 設計を決定します。非同期ホストを使用しても既存の TypeScript または JavaScript コードを壊さずに済めば完了です。