index.ts

export class ChatGptConversationService {
  /* ... */ 
  getConversationList = () => Promise.resolve(ConversationStorage);
  /* ... */
}

export class InMemoryConversationService implements ConversationService {
  /* ... */
  getConversationList = async (): Promise<ConversationList> => {
		const conversations = await this.chatgpt.getConversationList();
		if (!conversations) {
			return [];
		}
		return Object.keys(conversations).map<ConversationListEntry>((key) => {
			const firstMessage = conversations[key].messages.filter(
				(sm) => sm.role === "user"
			)[0];
			return {
				id: key,
				persona: conversations[key].persona,
				firstMessage: {
					text: String(firstMessage.content),
					sent: firstMessage.sent,
					source: firstMessage.role,
				},
			};
		});
	};
  /* ... */
}