How to properly specify / work with postgres text type in mikro-orm?

I have an entity that is storing a serialized json string. I initially had it declared as string type but started getting errors when it went over 255 characters. Postgres said it should be declared as a text type, so I referenced the MIKRO-ORM docs and see that they have a a text: TextType custom type.

I updated my entitities, and manually changed my db types as the migration wasn't picking up the change, but Typescript wasn't liking the new changes as trying to store a serialized json string into a text type yielded a Argument of type 'string' is not assignable to parameter of type 'TextType' error.

I was on a deadline so I just put a ts-ignore statement above, but I want to figure out what I'm doing wrong. The docs aren't clear to me and googling hasn't yielded any benefits.

Perhaps someone has insight into this?

import { TextType } from '@mikro-orm/core';

@Entity()
export class Event {
  ...

  @Property({ nullable: true })
  meta: TextType;

  ...

  constructor(
    ...
    meta?: TextType,
  ) {
    ...
    this.meta = meta || null;
  }
}

Thanks in advance!

Solution

You are confusing two things - the TS property type, which is what your runtime values will be mapped to - and that is still a string - and the mapped type that will be used to process the values and define the database column type - which is TextType.

The docs page you linked describes the t variable, that is a map of all provided mapped types, it just describes what you can use as an alias. All of the following should work the same (note that I also made the property optional on TS level, given you wanna mark is as nullable).

@Property({ type: TextType, nullable: true })
meta?: string;

@Property({ type: t.text, nullable: true })
meta?: string;

@Property({ type: 'text', nullable: true })
meta?: string;