Filter fields retrieved by eager? #1074
Description
I have Card, Tag and Project models.
Tag has a ManyToMany relationship with Card, Card has a ManyToMany relationship with Tag and Project.
I want to retrieve tags which are related to cards which in turn are related to a single project.
So I did this:
Tag
.query()
.eager('cards')
.joinRelation('[cards.[projects]]')
.where('cards:projects.id', req.query.projectId)
.groupBy('tags.id')
.then((tags) => {
res.json(tags);
})
.catch((error) => {
console.log(error);
res.send('An error occured');
});
However I don't want to retrieve all the Cards' properties, only the card id. So I added a filter to my Tag Model's relationMapping:
class Tag extends BaseModel {
static get tableName() {
return 'tags';
}
static get jsonSchema() {
return {
type: 'object',
required: ['title'],
properties: {
id: {type: 'integer'},
color: {type: 'string', minLength: 4, maxLength: 7},
bgColor: {type: 'string', minLength: 4, maxLength: 7},
tCreated: {type: 'string'},
tModified: {type: 'string'}
}
};
}
static get relationMappings() {
const Card = require('./card');
return {
cards: {
relation: BaseModel.ManyToManyRelation,
modelClass: Card,
filter: query => query.select('cards.id'),
join: {
from: 'tags.id',
through: {
from: 'cards_tags.tag_id',
to: 'cards_tags.card_id'
},
to: 'cards.id'
}
}
};
};
}
However, the query I displayed returns all properties of Card. If I change the filter to filter: query => query.select('id'), I get an error about id being ambiguous.
How can I limit eager('cards') so that it just returns card.id for each card?
(It would also be useful to include a field cardCount with each tag result, but I couldn't manage that in the same query - is that possible?)