Generic types

Generic types allows you to reduce code duplication. For example, if all your index endpoints return paginated responses it wouldn't be productive to write again and again the same class for each of your models.

Hopefully we can leverage mixins to avoid this.

import { ApiProperty, ApiBody } from '@foadonis/openapi/decorators'
 
function PaginatedResponse<TItem extends object>(Item: new (...args: any[]) => TItem) {
  abstract class Pagination {
    @ApiProperty()
    declare total: number
 
    @ApiProperty({ type: [Item] })
    declare items: TItem[]
  }
}
 
class RecipesPaginatedResponse extends PaginatedResponse(Recipe) {}
 
class UsersController {
  @ApiBody({ type: RecipesPaginatedResponse })
  index() {
    // ...
  }
}

Examples

Lucid Paginated response

In the following example we will create a mixin to create schemas for Lucid pagination.

app/controllers/users_controller.ts

import { HttpContext } from '@adonisjs/core/http'
import { ApiQuery } from '@foadonis/openapi/decorators'
import User from '#models/user'
 
export class UsersController {
  @ApiQuery({ name: 'page' })
  @ApiQuery({ name: 'limit' })
  index({ request }: HttpContext) {
    const page = request.input('page', 1)
    const limit = request.input('limit', 25)
    return User.query().paginate(page, limit)
  }
}

Meta schema

First we will need to create the schema for the meta property of our PaginatedResponse.

app/openapi/schemas/paginated_response.ts

import { ApiProperty } from '@foadonis/openapi/decorators'
 
export class PaginatedResponseMeta {
  @ApiProperty()
  declare total: number
 
  @ApiProperty()
  declare perPage: number
 
  @ApiProperty()
  declare currentPage: number
 
  @ApiProperty()
  declare lastPage: number
 
  @ApiProperty()
  declare firstPage: number
 
  @ApiProperty()
  declare firstPageUrl: string
 
  @ApiProperty()
  declare lastPageUrl: string
 
  @ApiProperty({ required: false })
  declare nextPageUrl?: string
 
  @ApiProperty({ required: false })
  declare previousPageUrl?: string
}

Mixin

We can now create a mixin that will have the properties data and meta.