How do you build a reusable pagination and sorting query DTO that can be extended by feature-specific DTOs in NestJS?

Q: How do you build a reusable pagination and sorting query DTO that can be extended by feature-specific DTOs in NestJS?

// Base pagination DTO export class PaginationDto { @IsOptional() @Type(() => Number) @IsInt() @Min(1) page: number = 1; @IsOptional() @Type(() => Number) @IsInt() @Min(1) @Max(100) limit: number = 20; get skip(): number { return (this.page - 1) * this.limit; } } // Sorting mixin export class SortDto { @IsOptional() @IsString() sortBy?: string = 'createdAt'; @IsOptional() @IsEnum(['ASC', 'DESC']) sortOrder?: 'ASC' | 'DESC' = 'DESC'; } // Feature-specific — extends both base DTOs export class UsersQueryDto extends IntersectionType(PaginationDto, SortDto) { @IsOptional() @IsString() search?: string; @IsOptional() @IsEnum(['active', 'inactive']) status?: 'active' | 'inactive'; } // Controller @Get() findAll(@Query() query: UsersQueryDto) { return this.usersService.findAll(query); } IntersectionType from @nestjs/mapped-types merges decorators from both parent classes. Also available from @nestjs/swagger — use that version to get Swagger integration automatically. The skip getter makes pagination DTOs directly usable with TypeORM findAndCount options. PartialType, PickType, and OmitType are other mapped-types utilities for DTO derivation. IntersectionType is the correct choice when you need ALL fields from both parents; PickType for a subset.

Difficulty: 5/10

DTO inheritance, pagination, sorting

Create base DTOs for pagination and sorting, then use IntersectionType from @nestjs/mapped-types to merge them into feature-specific DTOs. This preserves all class-validator decorators from both parent classes and ensures Swagger picks up all fields. Add a computed skip getter to the pagination base DTO for direct ORM use.

Reusable pagination and sorting DTOs

Reusable DTO composition patterns:

1
IntersectionType from @nestjs/mapped-types merges decorators from both parent classes.
2
Also available from @nestjs/swagger — use that version to get Swagger integration automatically.

How do you build a reusable pagination and sorting query DTO that can be extended by feature-specific DTOs in NestJS?

Difficulty: 5/10

DTO inheritance, pagination, sorting

Create base DTOs for pagination and sorting, then use IntersectionType from @nestjs/mapped-types to merge them into feature-specific DTOs. This preserves all class-validator decorators from both parent classes and ensures Swagger picks up all fields. Add a computed skip getter to the pagination base DTO for direct ORM use.

Reusable pagination and sorting DTOs

Reusable DTO composition patterns:

1
IntersectionType from @nestjs/mapped-types merges decorators from both parent classes.
2
Also available from @nestjs/swagger — use that version to get Swagger integration automatically.

How do you build a reusable pagination and sorting query DTO that can be extended by feature-specific DTOs in NestJS?

How do you build a reusable pagination and sorting query DTO that can be extended by feature-specific DTOs in NestJS?

Scenario Questions

Follow-up Questions