Can't use FindConditions with generics

[delucca]

Issue Description

Expected Behavior

While coding abstract classes for my application, I would like to use generic types as their entities and be able to execute a query.

Actual Behavior

I've created an abstract class that is extended by my entity services. While doing so, I have some methods that can execute queries. Everything is working as expected, but my type system breaks as soon as I use any method that uses FindCondition as an argument. Here is a minimal example:

abstract class GraphQLEntityResolver<E extends DomainEntity, D> {
  
  (...)

  public async getUserPolicies(selector: FindConditions<E>, user: AuthzUser) {
    const actionSelectors: AuthzScopeGroup = {
      [ACTION.CREATE]: user.scopes[this.resource][ACTION.CREATE],
      [ACTION.READ]: user.scopes[this.resource][ACTION.READ],
      [ACTION.UPDATE]: user.scopes[this.resource][ACTION.UPDATE],
      [ACTION.DELETE]: user.scopes[this.resource][ACTION.DELETE],
    }

    const policies: ActionPolicies = mapValues(
      actionSelectors,
      async (constraint, action: ACTION): Promise<POLICY> => {
        if (!constraint) return POLICY.DENY
        const foundData = await this.getOneWithActionScopeConstraint(selector, user, action)

        return foundData ? POLICY.ALLOW : POLICY.DENY
      },
    )

    return policies
  }

  @ResolveField('policies', () => PolicyObject)
  protected async getEntityPolicies(
    @Parent() entity: EntityObject,
    @GraphQLUser() user: AuthzUser,
  ) {
    const selector: FindConditions<E> = { id: entity.id }

    return this.getUserPolicies(selector, user)
  }
}

At the getEntityPolicies method, the selector I'm building is giving me the following error:

src/app/graphql/resolver.ts:138:11 - error TS2322: Type '{ id: string; }' is not assignable to type 'FindConditions<E>'.

But, here is the DomainEntity entity that I'm using:

export abstract class DomainEntity {
  @PrimaryGeneratedColumn('uuid')
  public id: string

  @CreateDateColumn()
  public createdAt: Date
}

Also, if I change my class to:

abstract class GraphQLEntityResolver<D> {

And always use DomainEntity instead of E, it works as expected.

So, it seems that FindConditions<E> is not considering the keys of the DomainEntity abstract entity class. Since it has id but the selector is complaining, saying that I can't use ID as a selector.

[imnotjames]

Looks like this was caused because by the jank in FindConditions types.

That was because Typescript 3.2 -> 3.6 had a problem with nested types. See #4470

However, it seems that this is no longer a problem with the latest versions ( > 3.6.3) so I'll be removing that workaround.