Implement TypeScript Request and Response Types

[lazarevtill]

Implement TypeScript Request and Response Types

Problem:
API routes lack consistent typing for request and response data.

Recommendation:
Define strict TypeScript interfaces for all API requests and responses.

// Create app/types/api.ts
export namespace API {
  // Chat API
  export namespace Chat {
    export interface Request {
      messages: Message[];
      chatId: string;
      userId: string;
      model: string;
      isAuthenticated: boolean;
      systemPrompt: string;
    }
    
    export interface Response {
      messageId?: string;
      error?: string;
      code?: string;
    }
  }
  
  // Rate limits API
  export namespace RateLimits {
    export interface Request {
      userId: string;
      isAuthenticated: boolean;
    }
    
    export interface Response {
      dailyCount: number;
      dailyLimit: number;
      remaining: number;
    }
  }
  
  // Add more API types...
}

// Use in API routes
import { API } from "@/app/types/api";

export async function POST(req: Request) {
  const requestData = await req.json() as API.Chat.Request;
  
  // Process request...
  
  const response: API.Chat.Response = {
    messageId: "123",
  };
  
  return new Response(JSON.stringify(response));
}

Impact: Medium - Improves type safety and code maintainability