Infer type when object coerced to string if toString explicitly defined

Search Terms

coercion toString computed properties

Suggestion

Infer type when object coerced to string if toString explicitly defined

Examples

Would be nice if the following would be allowed

const action = {
  type: 'foo',
  toString() { return this.type }
} as const;

const reducerHandler = {
  [action]: () => { } // Currently errors: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
}

Playground

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.

リンクされた TypeScript Playground の例を実行し、現在の computed-property-name エラーを調査します。明示的な toString 定義が型チェックにどのような影響を与えるべきかを判断し、そのうえで、出力される JavaScript を変更せずに例が受け入れられること、およびこの動作の coverage が追加されていることを確認します。