Typescript Definitely assigned fields problem when defining models

Following the typescript example, I created the following class:

import { Model } from '@nozbe/watermelondb'
import { field, children, date } from '@nozbe/watermelondb/decorators'

export default class Farm extends Model {
  static table = 'farms'

  static associations = {
    user: { type: 'has_many', foreignKey: 'user_id' },
    cattle: { type: 'has_many', foreignKey: 'cattle_id' },
  } as const

  @date('created_at') createdAt!: string
  @date('updated_at') updatedAt!: string

  @field('name') name!: string
  @field('car_number') carNumber!: string
  @field('car_data') carData!: string

  @children('users') users!: string
  @children('cattle') cattle!: string
}

When I save my file, TS throws the following error:

error: src/services/adapter/watermelonDB/models/Farm.ts: /home/angelo/Documentos/GIT/professional/databoi/databoi-front/src/services/adapter/watermelonDB/models/Farm.ts: Definitely assigned fields cannot be initialized here, but only in the constructor
  10 |   } as const
  11 | 
> 12 |   @date('created_at') createdAt!: string
     |   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  13 |   @date('updated_at') updatedAt!: string
  14 | 
  15 |   @field('name') name!: string

Turning off strictPropertyInitialization in tsconfig is not acceptable (I’d need to turn strict off and that defeats the purpose of strict typechecking).

Defining the variables inside a constructor, like below, gives me ExceptionsManager.js:179 Diagnostic error: Diagnostic error: Not allowed to change record outside of create/update() error.

import { Model } from '@nozbe/watermelondb'
import { field, children, date } from '@nozbe/watermelondb/decorators'

export default class Farm extends Model {
  constructor() {
    super()
    this.createdAt = ''
    this.updatedAt = ''
    this.name = ''
    this.carNumber = ''
    this.carData = ''
    this.users = ''
    this.cattle = ''
  }
  static table = 'farms'

  static associations = {
    user: { type: 'has_many', foreignKey: 'user_id' },
    cattle: { type: 'has_many', foreignKey: 'cattle_id' },
  } as const

  @date('created_at') createdAt
  @date('updated_at') updatedAt

  @field('name') name
  @field('car_number') carNumber
  @field('car_data') carData

  @children('users') users
  @children('cattle') cattle
}

How can I solve this problem?

[avinashlng1080]

hey @angelod1as , I was also facing this issue and this is what helped me.

The issue stems from the different @babel plugins and you would need to add a few and no need for a constructor.

Install the following babel plugins and add them under plugins in your babel.config.js file:

  plugins: [
        ['@babel/plugin-proposal-decorators', {legacy: true}],
        ['@babel/plugin-transform-flow-strip-types'],
        ['@babel/plugin-proposal-class-properties', {loose: true}],
        // add other plugins afterwards ....
]

[radex]

@angelod1as do it