Instruction file imported from hmake98/nestjs-starter (.github/instructions/interfaces.instructions.md). Copyright stays with the author.

Interface Conventions

Database entity interfaces (src/common/database/interfaces/)

import type { Post } from '@prisma/client';

// Entity is always a direct type alias from Prisma — never re-declared
export type PostEntity = Post;

// CreateInput: all fields required for creation (no id, createdAt, updatedAt, deletedAt)
export interface CreatePostInput {
    title: string;
    authorId: string;
    published?: boolean;
}

// UpdateInput: all fields optional
export interface UpdatePostInput {
    title?: string;
    published?: boolean;
}

Request interfaces (src/common/request/interfaces/)

// IAuthUser: what JwtAccessGuard puts on request.user
export interface IAuthUser {
    userId: string;
    role: UserRole;
}

Response interfaces (src/common/response/interfaces/)

• Mirror the DTO shape for use in interceptors/filters.
• Use generics for data payloads (IApiSuccessResponse<T>).

Rules

• Never use any — use unknown with type narrowing or a proper interface.
• No business logic in interface files — types and interfaces only.
• Import Prisma types with import type { X } from '@prisma/client' — always type import.