Agent-skills-standard nestjs-controllers-services

Separate Controllers from Services and build Custom Decorators in NestJS. Use when defining NestJS controllers, services, or custom parameter decorators. (triggers: **/*.controller.ts, **/*.service.ts, Controller, Injectable, ExecutionContext, createParamDecorator)

install

source · Clone the upstream repo

git clone https://github.com/HoangNguyen0403/agent-skills-standard

Claude Code · Install into ~/.claude/skills/

T=$(mktemp -d) && git clone --depth=1 https://github.com/HoangNguyen0403/agent-skills-standard "$T" && mkdir -p ~/.claude/skills && cp -r "$T/skills/nestjs/nestjs-controllers-services" ~/.claude/skills/hoangnguyen0403-agent-skills-standard-nestjs-controllers-services && rm -rf "$T"

manifest: skills/nestjs/nestjs-controllers-services/SKILL.md

source content

NestJS Controllers & Services Standards

Priority: P0 (FOUNDATIONAL)

Controllers

Role: Handler only. Delegate all logic to Services.
Context:
```
ExecutionContext
```
helpers (
```
switchToHttp()
```
) for platform-agnostic code.
Custom Decorators:
Avoid:
```
@Request() req
```
->
```
req.user
```
(Not type-safe).
Pattern: Create typed decorators like
```
@CurrentUser()
```
,
```
@DeviceIp()
```
.

import { RequestWithUser } from 'src/common/interfaces/request.interface';

export const CurrentUser = createParamDecorator(
  (data: unknown, ctx: ExecutionContext): User => {
    const request = ctx.switchToHttp().getRequest<RequestWithUser>();
    return request.user;
  },
);

DTOs & Validation

Strictness:
```
whitelist: true
```
: Strip properties without decorators.
Critical:
```
forbidNonWhitelisted: true
```
: Throw error if unknown properties exist.
Transformation:
```
transform: true
```
: Auto-convert primitives (String '1' -> Number 1) and instantiate DTO classes.
Documentation:
Swagger Plugin:
```
@nestjs/swagger
```
CLI plugin in
```
nest-cli.json
```
auto-detects DTO properties — no manual
```
@ApiProperty()
```
.

Interceptors (Response Mapping)

Map responses in Interceptors, not Controllers.
```
map()
```
wraps success responses (e.g.
```
{ data: T }
```
).
See API Standards for
```
PageDto
```
and
```
ApiResponse
```
.
```
catchError()
```
maps low-level errors (DB constraints) to
```
HttpException
```
(e.g.
```
ConflictException
```
) before global filter.

Services & Business Logic

Singleton: Default.
Stateless: No request-specific state in class properties unless
```
Scope.REQUEST
```
.

Pipes & Validation

Global: Register
```
ValidationPipe
```
globally.
Route Params: Fail fast. Always use
```
ParseIntPipe
```
,
```
ParseUUIDPipe
```
on all ID parameters.

@Get(':id')
findOne(@Param('id', ParseIntPipe) id: number) { ... }

Lifecycle Events

Init: Use
```
OnModuleInit
```
for connection setup.

Destroy: Use

OnApplicationShutdown

for cleanup. (Requires

enableShutdownHooks()

Anti-Patterns

No business logic in controllers: Delegate everything to Services; controllers only parse and respond.
No req.user access: Create typed
```
@CurrentUser()
```
decorator instead of accessing raw
```
req
```
.
No REQUEST scope by default: Use SINGLETON; it makes entire injection chain request-scoped.

References

Decorator, Pipe & Lifecycle Examples