typescript-api-types

name	typescript-api-types
description	Apply when defining API request/response types, DTOs, and shared types between frontend and backend.
version	1.1.0
tokens	~650
confidence	high
sources	["https://www.typescriptlang.org/docs/handbook/utility-types.html","https://zod.dev/"]
last_validated	2025-12-10T00:00:00.000Z
next_review	2025-12-24T00:00:00.000Z
tags	["typescript","api","types","validation"]

When to Use

Apply when defining API request/response types, DTOs, and shared types between frontend and backend.

Patterns

Pattern 1: Request/Response Types

// Source: https://www.typescriptlang.org/docs/handbook/utility-types.html
// Base entity
interface User {
  id: string;
  email: string;
  name: string;
  createdAt: Date;
  updatedAt: Date;
}

// Create DTO (omit auto-generated fields)
type CreateUserDto = Omit<User, 'id' | 'createdAt' | 'updatedAt'>;

// Update DTO (all fields optional except id)
type UpdateUserDto = Partial<Omit<User, 'id'>> & Pick<User, 'id'>;

// Response (dates as strings from JSON)
type UserResponse = Omit<User, 'createdAt' | 'updatedAt'> & {
  createdAt: string;
  updatedAt: string;
};

Pattern 2: API Response Wrapper

// Source: Best practice pattern
interface <T> {
  : T;
  ?: {
    ?: ;
    ?: ;
    ?: ;
  };
}

  {
  : {
    : ;
    : ;
    ?: <, []>;
  };
}

 <T> = <T> | ;


 (): result is  {
     result;
}