How to join related tree repository with TypeORM - nestjs

Question

I have this situation:
This is my tree entity where each item can be a parent item or child item of one of the same entity and each of them are related to an artist.
#Entity()
#Tree("materialized-path")
export class ArtistCommissionSetupItem {
#PrimaryGeneratedColumn({type: "bigint"})
id:number
#ManyToOne(()=>Artist, artist => artist.id, {onDelete: 'CASCADE'})
#JoinColumn()
#Index()
artist:Artist
#Column()
#Index()
name:string
#Index()
#Column({nullable: true})
enabled:boolean
#TreeParent()
parent:ArtistCommissionSetupItem
#TreeChildren()
childrens:ArtistCommissionSetupItem[]
}
The thing here is that I want to get the artist with his related commission setup items and I can do that but the result of commission setup items leftJoinAndSelect method doesn't come with the items nested as tree/child tree. I want the data of commission setup items come like findTrees() method returns it.
An example of how the data come:
"commissionSetupItems": [
{
"id": "154",
"name": "Body",
"enabled": null,
"price": null,
"createdAt": "2021-09-23T21:17:05.630Z",
"updatedAt": "2021-09-23T21:17:05.630Z"
},
{
"id": "155",
"name": "icon",
"enabled": true,
"price": "120.00",
"createdAt": "2021-09-23T21:17:05.630Z",
"updatedAt": "2021-09-23T21:17:05.630Z"
},
{
"id": "156",
"name": "Headshot",
"enabled": false,
"price": "120.00",
"createdAt": "2021-09-23T21:17:05.630Z",
"updatedAt": "2021-09-23T21:17:05.630Z"
}
}
an example of how I want the data comes:
{
"commissionSetupItems": [
{
"id": 1,
"name": "Characters",
"key": "characters",
"childrens": [
{
"id": 5,
"name": "Number of characters",
"key": "number_of_characters",
"childrens": []
}
]
},
{
"id": 2,
"name": "Body",
"key": "body",
"childrens": [
{
"id": 6,
"name": "Icon",
"key": "icon",
"childrens": []
},
{
"id": 7,
"name": "Chibi",
"key": "chibi",
"childrens": []
},
{
"id": 8,
"name": "Headshot",
"key": "headshot",
"childrens": []
},
{
"id": 9,
"name": "Torso or Burst",
"key": "torso",
"childrens": []
},
{
"id": 10,
"name": "Half body",
"key": "half_body",
"childrens": []
},
{
"id": 11,
"name": "Full body",
"key": "full_body",
"childrens": []
}
]
}
}
I can't figure out how to do this.