@adocasts.com/dto

Easily make and generate DTOs from Lucid Models

Converting Lucid Models to DTO files can be a tedious task. This package aims to make it a little less so by reading your model's property definitions and porting them to a DTO. Will it be perfect? Likely not, but it should help cut back on the repetition needed to complete the task.

Installation

You can easily install and configure via the Ace CLI's add command.

node ace add @adocasts.com/dto

Manual Install & Configure

You can also manually install and configure if you'd prefer

npm install @adocasts.com/dto

node ace configure @adocasts.com/dto

Define DTO Import Path

The generated DTOs will use #dtos/* for relationship imports within the DTOs. As such, we recommend defining this import path within your package.json

"imports": {
  "#dtos/*": "./app/dtos/*.js"
}

Generate DTOs Command

Want to generate DTOs for all your models in one fell swoop? This is the command for you!

node ace generate:dtos

This will read all of your model files, collecting their properties and types. It'll then convert those property's types into serialization-safe types and relationships into their DTO representations.

File Tree                       Class
------------------------------------------------
└── app/
    ├── dtos/
    │   ├── account.ts          AccountDto
    │   ├── account_group.ts    AccountGroupDto
    │   ├── account_type.ts     AccountTypeDto
    │   ├── income.ts           IncomeDto
    │   ├── payee.ts            PayeeDto
    │   └── user.ts             UserDto
    └── models/
        ├── account.ts          Account
        ├── account_group.ts    AccountGroup
        ├── account_type.ts     AccountType
        ├── income.ts           Income
        ├── payee.ts            Payee
        └── user.ts             User

• Gets a list of your model files from the location defined within your adonisrc.ts file
• Reads those files as plaintext, filering down to just property definitions
• Determines the property name, it's types, whether it's a relationship, and if it's optionally modified ?
• Converts those model types into serialized representations (currently a very loose conversion)
  • Note, at present, this does not account for serialization behaviors defined on the model property (like serializeAs)
• Creates DTO property definitions from those conversions
• Prepares constructor value setters for each property
• Collects needed imports for relationships
• Generates the DTO file
  • Note, if a file already exists at the DTOs determined location it will be skipped

Make DTO Command

Want to make a plain DTO file, or a single DTO from a single Model? This is the command for you!

To make a DTO named AccountDto within a file located at dto/account.ts, we can run the following:

node ace make:dto account

This will check to see if there is a model named Account. If a model is found, it will use that model's property definitions to generate the AccountDto. Otherwise, it'll generate just a AccountDto file with an empty class inside it.

File Tree                       Class
------------------------------------------------
└── app/
    ├── dtos/
    │   ├── account.ts          AccountDto
    └── models/
        ├── account.ts          Account

What If There Isn't An Account Model?

As mentioned above, a plain AccountDto class will be generated within a new dto/account.ts file, which will look like the below.

export default class AccountDto {}

Specifying A Different Model

If the DTO and Model names don't match, you can specify a specific Model to use via the --model flag.

node ace make:dto account --model=main_account

Now instead of looking for a model named Account it'll instead look for MainAccount and use it to create a DTO named AccountDto.

BaseDto Helpers

Newly added in v0.0.4, we now include either a BaseDto or BaseModelDto depeneding on whether we're generating your DTO from a model or not. Both of these bases include a helper called fromArray. With this, you can pass in an array of source objects. We'll then loop over them and pass each into a new constructor. This does run with the assumption that you'll populate properties within your DTO constructors.

Here's a quick example

class Test extends BaseModel {
  @column()
  declare id: number
}

class TestDto extends BaseModelDto {
  declare id: number

  constructor(instance: Test) {
    super()
    this.id = instance.id
  }
}

const tests = await Test.createMany([{ id: 1 }, { id: 2 }, { id: 3 }])

const dtoArray = TestDto.fromArray(tests)
// [TestDto, TestDto, TestDto]

Additionally, BaseModelDto also includes a fromPaginator helper. This allows you to pass in an instance of the ModelPaginator to be converted into a SimplePaginatorDto we have defined within this package. You can also pass in a URL range start and end and we'll generate those URLs for you during the conversion.

Here's a simple example

class Test extends BaseModel {
  @column()
  declare id: number
}

class TestDto extends BaseModelDto {
  declare id: number

  constructor(instance: Test) {
    super()
    this.id = instance.id
  }
}

const tests = await Test.createMany([{ id: 1 }, { id: 2 }, { id: 3 }])

const paginator = await Test.query().paginate(1, 2)
const paginatorDto = TestDto.fromPaginator(paginator, { start: 1, end: 2 })
/**
 * {
 *    data: TestDto[],
 *    meta: SimplePaginatorDtoMetaContract
 * }
 */

const paginationUrls = paginatorDto.meta.pagesInRange
/**
 * [
 *    {
 *      url: '/?page=1',
 *      page: 1,
 *      isActive: true
 *    },
 *    {
 *      url: '/?page=2',
 *      page: 2,
 *      isActive: false
 *    },
 * ]
 */

If, for example, you're using something like Inertia, you can then type your props accordingly

import { SimplePaginatorDtoContract } from '@adocasts.com/dto/types'
import DifficultyDto from '#dtos/difficulty'

const props = defineProps<{
  paginated: SimplePaginatorDtoContract<DifficultyDto>
}>()

const rows = props.paginated.data
const info = props.paginated.meta
const urls = props.paginated.meta.pagesInRange

Things To Note

• At present we assume the Model's name from the file name of the model.
• There is NOT currently a setting to change the output directory of the DTOs
• Due to reflection limitations, we're reading Models as plaintext. I'm no TypeScript wiz, so if you know of a better approach, I'm all ears!
  • Since we're reading as plaintext
    • Currently we're omitting decorators and their options

Example

So, we've use account as our example throughout this guide, so let's end by taking a look at what this Account Model looks like!

The Account Model

// app/models/account.ts

import { DateTime } from 'luxon'
import { BaseModel, belongsTo, column, computed, hasMany, hasOne } from '@adonisjs/lucid/orm'
import User from './user.js'
import type { BelongsTo, HasMany, HasOne } from '@adonisjs/lucid/types/relations'
import AccountType from '#models/account_type'
import Payee from '#models/payee'
import Stock from '#models/stock'
import Transaction from '#models/transaction'
import AccountTypeService from '#services/account_type_service'
import { columnCurrency } from '#start/orm/column'
import type { AccountGroupConfig } from '#config/account'

export default class Account extends BaseModel {
  // region Columns

  @column({ isPrimary: true })
  declare id: number

  @column()
  declare userId: number

  @column()
  declare accountTypeId: number

  @column()
  declare name: string

  @column()
  declare note: string

  @column.date()
  declare dateOpened: DateTime | null

  @column.date()
  declare dateClosed: DateTime | null

  @columnCurrency()
  declare balance: number

  @columnCurrency()
  declare startingBalance: number

  @column.dateTime({ autoCreate: true })
  declare createdAt: DateTime

  @column.dateTime({ autoCreate: true, autoUpdate: true })
  declare updatedAt: DateTime

  // endregion

  // region Unmapped Properties

  aggregations: Record<string, number> = {}

  // endregion

  // region Relationships

  @belongsTo(() => User)
  declare user: BelongsTo<typeof User>

  @belongsTo(() => AccountType)
  declare accountType: BelongsTo<typeof AccountType>

  @hasOne(() => Payee)
  declare payee: HasOne<typeof Payee>

  @hasMany(() => Stock)
  declare stocks: HasMany<typeof Stock>

  @hasMany(() => Transaction)
  declare transactions: HasMany<typeof Transaction>

  // endregion

  // region Computed Properties

  @computed()
  get accountGroup(): AccountGroupConfig {
    return AccountTypeService.getAccountTypeGroup(this.accountTypeId)
  }

  @computed()
  get isCreditIncrease(): boolean {
    return AccountTypeService.isCreditIncreaseById(this.accountTypeId)
  }

  @computed()
  get isBudgetable() {
    return AccountTypeService.isBudgetable(this.accountTypeId)
  }

  @computed()
  get balanceDisplay() {
    return '$' + this.balance.toLocaleString('en-US')
  }

  // endregion
}

It's got

• Column properties
• Nullable properties
• An unmapped property, which also contains a default value
• Getters
• Relationships

Let's see what we get when we generate our DTO!

node ace make:dto account

The Account DTO

import { BaseModelDto } from '@adocasts.com/dto/base'
import Account from '#models/account'
import UserDto from '#dtos/user'
import AccountTypeDto from '#dtos/account_type'
import PayeeDto from '#dtos/payee'
import StockDto from '#dtos/stock'
import TransactionDto from '#dtos/transaction'
import { AccountGroupConfig } from '#config/account'

export default class AccountDto extends BaseModelDto {
  declare id: number
  declare userId: number
  declare accountTypeId: number
  declare name: string
  declare note: string
  declare dateOpened: string | null
  declare dateClosed: string | null
  declare balance: number
  declare startingBalance: number
  declare createdAt: string
  declare updatedAt: string
  aggregations: Record<string, number> = {}
  declare user: UserDto | null
  declare accountType: AccountTypeDto | null
  declare payee: PayeeDto | null
  declare stocks: StockDto[]
  declare transactions: TransactionDto[]
  declare accountGroup: AccountGroupConfig
  declare isCreditIncrease: boolean
  declare isBudgetable: boolean
  declare balanceDisplay: string

  constructor(account?: Account) {
    super()

    if (!account) return
    this.id = account.id
    this.userId = account.userId
    this.accountTypeId = account.accountTypeId
    this.name = account.name
    this.note = account.note
    this.dateOpened = account.dateOpened?.toISO()!
    this.dateClosed = account.dateClosed?.toISO()!
    this.balance = account.balance
    this.startingBalance = account.startingBalance
    this.createdAt = account.createdAt.toISO()!
    this.updatedAt = account.updatedAt.toISO()!
    this.aggregations = account.aggregations
    this.user = account.user && new UserDto(account.user)
    this.accountType = account.accountType && new AccountTypeDto(account.accountType)
    this.payee = account.payee && new PayeeDto(account.payee)
    this.stocks = StockDto.fromArray(account.stocks)
    this.transactions = TransactionDto.fromArray(account.transactions)
    this.accountGroup = account.accountGroup
    this.isCreditIncrease = account.isCreditIncrease
    this.isBudgetable = account.isBudgetable
    this.balanceDisplay = account.balanceDisplay
  }
}

It's got the

• Needed imports (it'll try to get them all by also referencing the Model's imports)
• Column properties from our Model
• Nullable property's nullability
• Unmapped property from our Model, plus it's default value
• Relationships converted into DTO representations
• Getters and their types, when specified. If types are inferred, the type will default to string or boolean if variable name starts with is
• Constructor value setters for all of the above
• A helper method fromArray that'll normalize to an empty array if need be