`leftJoinAndMapOne` doesn't add property when custom query builder is used

[prateekkathal]

Issue Description

Coming from #1882. Running a query builder in leftJoinAndMapOne doesn't map to property.

Expected Behavior

leftJoinAndMapOne should map to the provided property.

Actual Behavior

I am trying to do something like

const [venues, venuesCount] = this.venuesRepository
  .createQueryBuilder("Venue")
  .leftJoinAndSelect("Venue.city", "city")
  .leftJoinAndMapOne(
    "Venue.eventStats",
    (qb) =>
      qb
        .from("events", "Event")
        .select('"venueId"')
        .addSelect(`MAX("capacity")`, "maxVenueCapacity")
        .addSelect(`COUNT("venueId")`, "eventsCount")
        .groupBy('"venueId"'),
    "Event",
    "Venue.id = Event.venueId"
  )
  .where(`Venue.cityId = :cityId`, { cityId: "someCityId" })
  .orderBy(`eventCount`, `DESC`)
  .getManyAndCount();

And my model has

interface EventStats {
  maxVenueCapacity: number;
  eventsCount: number;
}

@Entity()
class Venue {
  eventStats: EventStats;
}

at the end venues[].eventStats is not added.

// include the output in code tags like these!

Steps to Reproduce

1. Use the code I provided above to create a similar query.
2. Run the query and check if the mapped property is getting added.

My Environment

Dependency	Version
Operating System	Docker Node Alpine Image
Node.js version	14.17.0
Typescript version	4.5.4
TypeORM version	0.2.41

Additional Context

Relevant Database Driver(s)

DB Type	Reproducible
postgres	yes

Are you willing to resolve this issue by submitting a Pull Request?

• ✖️ Yes, I have the time, but I don't know how to start. I would need guidance.

[JE-lee]

is still a issue

[acuthbert]

From what I can see the issue is that unless you use an Entity class or a relation property, typeorm cannot know what the mappings are from the properties on the custom query.

One solution seems fairly simple - have an extra argument on this overload for the user to supply the correct Entity class constructor to use for the mapping. Though this is so simple I'm wondering if there's a reason this hasn't already been done. From what I can see this issue has been present for a long time.

@prateekkathal does that help you in anyway to put an MR together for it?

[acuthbert]

@prateekkathal I've created an MR to fix this - although the user has to pass the entity for the mapping as it might not always be able to get this from the joined query builder.

[prateekkathal]

@prateekkathal I've created an MR to fix this - although the user has to pass the entity for the mapping as it might not always be able to get this from the joined query builder.

Thanks for creating the PR. I leave it up to the mods/admins to approve the solution. Personally I feel that defining the property inside the Entity itself should automatically map it. I think we should understand the reasoning as to why it doesn't do it now when it already works for other entities rather than just adding another parameter. But if the admins agree with your solution, nothing like it 😄

Once again, thanks for taking the lead here. I missed your last message and never personally got the chance to contribute. Glad that you could!

Looking forward to a solution getting merged! 👍