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[ember-data] references API is not compatible with typescript@3.9 and higher

See original GitHub issue

The problem appears when you try to use this.belongsTo( or this.hasMany( in scope of a model method or accesor. In this case this is broken, and it complains about the invalid invocation, until this type is explicitly specified in the method signature.

Unfortunately, an explicit this workaround doesn’t work for accesors in typescript@3.9 and higher, since they forbidden to specify this on getters/setters, see https://github.com/microsoft/TypeScript/issues/39254#issuecomment-649831793.

Which package(s) does this problem pertain to?

What are instructions we can follow to reproduce the issue?


export default class User extends Model {
  @belongsTo("user")
  friend!: AsyncBelongsTo<User>;

  // `this: User` leads to the following compilation error:
  // > get' and 'set' accessors cannot declare 'this' parameters.t
  get friendId(this: User) {
    // if don't specify `this`, it'd fail on the next line
    return this.belongsTo("friend").value()?.id;
  }
}

Reproduction Case

Link: https://codesandbox.io/s/my-app-forked-zqghf?file=/app/models/user.ts

Now about that bug. What did you expect to see?

I expect:

export default class User extends Model {
  @belongsTo("user")
  friend!: AsyncBelongsTo<User>;

  get friendId() {
    return this.belongsTo("friend").value()?.id;
  }
}

to work w/o a need for explicit this and compilation errors.

What happened instead?

If remove an explicit this from the signature,

  return this.belongsTo("friend").value()?.id;

would lead to a compilation error:

Argument of type ‘string’ is not assignable to parameter of type ‘Exclude<keyof this, “isEmpty” | “isLoading” | “isLoaded” | “hasDirtyAttributes” | “isSaving” | “isDeleted” | “isNew” | “isValid” | “dirtyType” | “isError” | “isReloading” | “id” | … 41 more … | “toString”>’.ts(2345) Compilation error:

Issue Analytics

State:
Created 3 years ago
Reactions:4
Comments:5 (3 by maintainers)

Top GitHub Comments

1reaction

JarrettSpikercommented, Jul 25, 2022

My workaround ended up being

  get friendId() {
    let inst = this as User;
    return this.belongsTo("friend").value()?.id;
  }

though I suspect I may be encountering a slightly separate issue

1reaction

ro0grcommented, Mar 17, 2021

A while ago, I did a PR(https://github.com/DefinitelyTyped/DefinitelyTyped/pull/42839), which fixed the belongsTo(, hasMany( return types. And as a side effect, it did also fix this corrupted this issue.

Unfortunately it has never been merged. Happy to reopen it.