v0.22.x to v0.23.x

Offset Paging Strategy [BREAKING CHANGE]​

In previous versions of nestjs-query the OFFSET paging strategy returned an array of nodes, this proved to not be extensible, especially when wanting to expose other attributes such as totalCount, or paging meta such has hasNextPage or hasPreviousPage.

In v0.23.0 the graphql response now returns an OffsetConnection that looks like the following

type OffsetPageInfo {
  hasNextPage: Boolean
  hasPreviousPage: Boolean
}
type TodoItemConnection {
  pageInfo: OffsetPageInfo!
  nodes: [TodoItem!]!
}
type TodoItem {
  id: ID!
  title: String!
  description: String
  completed: Boolean!
  created: DateTime!
  updated: DateTime!
}

Total Count with OFFSET Strategy​

In previous versions of the nestjs-query the enableTotalCount option only worked with the CURSOR paging strategy. In v0.23.0 the enableTotalCount option now also works with the OFFSET paging strategy.

When enableTotalCount is set to true the following graphql schema will be generated

type OffsetPageInfo {
  hasNextPage: Boolean
  hasPreviousPage: Boolean
}
type TodoItemConnection {
  totalCount: Int!
  pageInfo: OffsetPageInfo!
  nodes: [TodoItem!]!
}
type TodoItem {
  id: ID!
  title: String!
  description: String
  completed: Boolean!
  created: DateTime!
  updated: DateTime!
}

Relation Decorator Changes [BREAKING CHANGE]​

In previous versions of nestjs-query there were four relation decorators @Relation, @FilterableRelation, @Connection, and @FilterableConnection all four of the decorators have been changed to be more explicit in naming to be clear in what they are doing.

In v0.23.0 the decorators have been renamed to be more explicit.

• @Relation - A relation that is a single value (one-to-one, many-to-one)
• @FilterableRelation - A @Relation that enables filtering the parent by fields of the relation DTO.
• @UnPagedRelation - An array of relations (e.g, many-to-many, one-to-many) that returns all the related records.
• @FilterableUnPagedRelation - An @UnPagedRelation that enables filtering the parent by fields of the relation DTO.
• @OffsetConnection - A connection that represents a collection (e.g, many-to-many, one-to-many) that uses offset based pagination.
• @FilterableOffsetConnection - An @OffsetConnection that enables filtering the parent by fields of the connection DTO.
• @CursorConnection - A connection that represents a collection (e.g, many-to-many, one-to-many) that uses cursor based pagination.
• @FilterableCursorConnection - A @CursorConnection that enables filtering the parent by fields of the connection DTO.

Below is a mapping of the old definition to the new one

In previous versions the OFFSET paging strategy returned an array of relations, the new version returns an OffsetConnection

//old

@Relation('subTasks', () => [TodoItem])
//new

@OffsetConnection('subTasks', () => TodoItem)

//old

@FilterableRelation('subTasks', () => [TodoItem])
//new

@FilterableOffsetConnection('subTasks', () => TodoItem)

//old

@Relation('subTasks', () => [TodoItem], {pagingStrategy: PagingStrategies.NONE})
//new

@UnPagedRelation('subTasks', () => TodoItem)

//old

@FilterableRelation('subTasks', () => [TodoItem], {pagingStrategy: PagingStrategies.NONE})
//new

@FilterableUnPagedRelation('subTasks', () => TodoItem)

//old

@Connection('subTasks', () => TodoItem)
//new

@CursorConnection('subTasks', () => TodoItem)

//old

@FilterableConnection('subTasks', () => TodoItem)
//new

@FilterableCursorConnection('subTasks', () => TodoItem)

Authorizers​

In previous versions of nestjs-query the resolvers relied on an AuthorizerService to be injected and the filters were created manually within the resolver.

In the latest version, we have transitioned to a interceptor/param decorator pattern. This provides:

• Better separation of concerns, auth filters are now just params passed to the resolver method.
• More flexibility when extending the resolvers to reuse the same logic that the auto-generated resolvers use without having to worry about internal implementation details.
• Easier extension of the CRUDResolver by not having to worry about injecting the authorizerService, it will automatically add the interceptor and param decorators to auto generated methods, you just need to decorate your DTO.
• Familiar patterns that are laid out in the core nestjs documentation.

Old way

import { QueryService, InjectQueryService } from '@ptc-org/nestjs-query-core'
import { CRUDResolver } from '@ptc-org/nestjs-query-graphql'
import { Resolver, Query, Args } from '@nestjs/graphql'
import { TodoItemDTO } from './dto/todo-item.dto'
import { TodoItemEntity } from './todo-item.entity'

@Resolver(() => TodoItemDTO)
export class TodoItemResolver {

  constructor(
    @InjectQueryService(TodoItemEntity) readonly service: QueryService<TodoItemEntity>,
    @InjectAuthorizer(TodoItemDTO) readonly authorizer: Authorizer<TodoItemDTO>
  ) {}

  @Query(() => TodoItemConnection)
  async uncompletedTodoItems(@Args() query: TodoItemQuery, @Context() context: unknown): Promise<ConnectionType<TodoItemDTO>> {
    // add the completed filter the user provided filter
    const authFilter = this.authorizer.authorize(context)
    const filter: Filter<TodoItemDTO> = mergeFilter(query.filter ?? {}, { completed: { is: false } })
    const uncompletedQuery = mergeQuery(query, { filter: mergeFilter(filter, authFilter) })
    return TodoItemConnection.createFromPromise(
      (q) => this.service.query(q),
      uncompletedQuery,
      (q) => this.service.count(q)
    )
  }
}

New

import { Filter, InjectQueryService, mergeFilter, mergeQuery, QueryService } from '@ptc-org/nestjs-query-core'
import { AuthorizerInterceptor, AuthorizerFilter, ConnectionType } from '@ptc-org/nestjs-query-graphql'
import { Args, Query, Resolver } from '@nestjs/graphql'
import { UseInterceptors } from '@nestjs/common'
import { TodoItemDTO } from './dto/todo-item.dto'
import { TodoItemConnection, TodoItemQuery } from './types'

@Resolver(() => TodoItemDTO)
@UseInterceptors(AuthorizerInterceptor(TodoItemDTO))
export class TodoItemResolver {

  constructor(@InjectQueryService(TodoItemEntity) readonly service: QueryService<TodoItemEntity>) {}
  // Set the return type to the TodoItemConnection

  @Query(() => TodoItemConnection)
  async uncompletedTodoItems(
    @Args() query: TodoItemQuery,
    @AuthorizerFilter() authFilter: Filter<TodoItemDTO>
  ): Promise<ConnectionType<TodoItemDTO>> {
    // add the completed filter the user provided filter
    const filter: Filter<TodoItemDTO> = mergeFilter(query.filter ?? {}, { completed: { is: false } })
    const uncompletedQuery = mergeQuery(query, { filter: mergeFilter(filter, authFilter) })
    return TodoItemConnection.createFromPromise(
      (q) => this.service.query(q),
      uncompletedQuery,
      (q) => this.service.count(q)
    )
  }
}

Hook Updates​

In previous versions of nestjs-query hooks were not very flexible, and could not be used by custom resolver endpoints.

In the latest version the hooks pipeline has been re-worked to enable the following:

• Hook decorators now accept either a hook funciton OR a custom hook class that can use dependency injection.
• Reusing hooks in custom endpoints.

As a demonstration of the flexibility of the new hooks implementation, lets use a hook in a custom endpoint (this would not have been possible previously)

import { InjectQueryService, mergeFilter, QueryService, UpdateManyResponse } from '@ptc-org/nestjs-query-core'
import { HookTypes, HookInterceptor, MutationHookArgs, UpdateManyResponseType } from '@ptc-org/nestjs-query-graphql'
import { UseInterceptors } from '@nestjs/common'
import { Mutation, Resolver } from '@nestjs/graphql'
import { TodoItemDTO } from './dto/todo-item.dto'
import { TodoItemEntity } from './todo-item.entity'
import { UpdateManyTodoItemsArgs } from './types'

@Resolver(() => TodoItemDTO)
export class TodoItemResolver {

  constructor(@InjectQueryService(TodoItemEntity) readonly service: QueryService<TodoItemDTO>) {}

  @Mutation(() => UpdateManyResponseType())
  @UseInterceptors(HookInterceptor(HookTypes.BEFORE_UPDATE_MANY, TodoItemDTO))
  markTodoItemsAsCompleted(@MutationHookArgs() { input }: UpdateManyTodoItemsArgs): Promise<UpdateManyResponse> {
    return this.service.updateMany({ ...input.update, completed: false }, mergeFilter(input.filter, { completed: { is: false } }))
  }
}

The two important things are:

• The HookInterceptor in this example we reuse the BEFORE_UPDATE_MANY hook on the TodoItemDTO, the interceptor adds a DI hook instance to the context that can be used downstream by any guards or param decorators.
• @MutationHookArgs will apply the correct hook to the args and provide it to the resolver endpoint.

In this next example we can demonstrate the DI capability, we’ll keep the example simple, but with nestjs’s DI functionality you can inject other services to look up information and transform the incoming request as much as you need.

In this example we create a simple hook that will work for both createOne and createMany endpoints to set the createdBy attribute. In this example we look up the userEmail from the userService and set createdBy attribute on the input.

interface CreatedBy {

  createdBy: string
}

@Injectable()
export class CreatedByHook<T extends CreatedBy>
  implements BeforeCreateOneHook<T, GqlContext>, BeforeCreateManyHook<T, GqlContext>
{
  constructor(readonly userService: UserService) {}
  run(instance: CreateManyInputType<T>, context: GqlContext): Promise<CreateManyInputType<T>>
  run(instance: CreateOneInputType<T>, context: GqlContext): Promise<CreateOneInputType<T>>
  async run(
    instance: CreateOneInputType<T> | CreateManyInputType<T>,
    context: GqlContext
  ): Promise<CreateOneInputType<T> | CreateManyInputType<T>> {
    const createdBy = await this.userService.getUserEmail(context.req.userId)
    if (Array.isArray(instance.input)) {
      // eslint-disable-next-line no-param-reassign
      instance.input = instance.input.map((c) => ({ ...c, createdBy }))
      return instance
    }
    // eslint-disable-next-line no-param-reassign
    instance.input.createdBy = createdBy
    return instance
  }
}

Now we can use this generic hook on any DTO that has a createdBy field

@InputType('TodoItemInput')
@BeforeCreateOne(CreatedByHook)
@BeforeCreateMany(CreatedByHook)
export class TodoItemInputDTO {

  @IsString()
  @MaxLength(20)
  @Field()
  title!: string

  @IsBoolean()
  @Field()
  completed!: boolean
  // don't annotate with field because its set by the hook
  createdBy!: string
}

Registering DTOs When Using Custom Resolvers​

In previous versions of nestjs-query you could extend CRUDResolver but there was not a way to set up the appropriate providers for many of the newer features (hooks, authorizers etc.).

In the latest version you now have the option to register your DTOs with @ptc-org/nestjs-query-graphql without it generating a resolver automatically.

In this example we create a custom resolver that extends CRUDResolver.

todo-item.resolver.ts

import { QueryService, InjectQueryService } from '@ptc-org/nestjs-query-core'
import { CRUDResolver } from '@ptc-org/nestjs-query-graphql'
import { Resolver, Query, Args } from '@nestjs/graphql'
import { TodoItemDTO } from './dto/todo-item.dto'
import { TodoItemEntity } from './todo-item.entity'

@Resolver(() => TodoItemDTO)
export class TodoItemResolver extends CRUDResolver(TodoItemDTO) {

  constructor(@InjectQueryService(TodoItemEntity) readonly service: QueryService<TodoItemEntity>) {
    super(service)
  }
}

Because the TodoItemResolver extends CRUDResolver there is no need to have nestjs-query also create a resolver, instead you can specify the dtos option which just takes in DTOClass, CreateDTOClass, and UpdateDTOClass to set up all of additional providers to hooks, authorizers and other features.

todo-item.module.ts

import { NestjsQueryGraphQLModule } from '@ptc-org/nestjs-query-graphql'
import { NestjsQueryTypeOrmModule } from '@ptc-org/nestjs-query-typeorm'
import { Module } from '@nestjs/common'
import { TodoItemDTO } from './todo-item.dto'
import { TodoItemEntity } from './todo-item.entity'
import { TodoItemResolver } from './todo-item.resolver'

@Module({
  providers: [TodoItemResolver],
  imports: [
    NestjsQueryGraphQLModule.forFeature({
      imports: [NestjsQueryTypeOrmModule.forFeature([TodoItemEntity])],
      dtos: [{ DTOClass: TodoItemDTO }]
    })
  ]
})
export class TodoItemModule {}

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