Lucid: how to hiding "pivot" attribute from belongsToMany relationships?

[italoiz]

I have a belongsToMany relationship, but I'd like to hide the "pivot" attribute of the output in JSON.

[thetutlage]

Can you share the code you are running?

[italoiz]

I have model with code below:

A Class related to Courses, Students and Teachers.

'use strict'

const Model = use('Model')

class Class extends Model {
  /**
   * Filter by class.
   *
   * @param {*} query
   * @param {*} type
   */
  static scopeByClass (query, class_id) {
    if (class_id) {
      if (class_id instanceof Array) {
        query.whereIn('id', class_id)
      } else {
        query.where('id', class_id)
      }
    }
  }

  /**
   * Filter by course.
   *
   * @param {*} query
   * @param {*} type
   */
  static scopeByCourse (query, course_id) {
    if (course_id) {
      query.whereHas('courses', query => {
        if (course_id instanceof Array) {
          query.whereIn('course_id', course_id)
        } else {
          query.where('course_id', course_id)
        }
      })
    }
  }

  /**
   * Filter by teacher.
   *
   * @param {*} query
   * @param {*} type
   */
  static scopeByTeacher (query, teacher_id) {
    if (teacher_id) {
      query.whereHas('teachers', query => {
        if (teacher_id instanceof Array) {
          query.whereIn('user_id', teacher_id)
        } else {
          query.where('user_id', teacher_id)
        }
      })
    }
  }

  /**
   * Teachers.
   *
   * @return Array<User>
   */
  teachers () {
    // return this.hasMany('App/Models/ClassTeacher')
    return this.belongsToMany('App/Models/User').pivotModel(
      'App/Models/ClassTeacher'
    )
  }

  /**
   * Courses.
   *
   * @return Array<Course>
   */
  courses () {
    return this.belongsToMany('App/Models/Course').pivotModel(
      'App/Models/ClassCourse'
    )
  }

  /**
   * Students
   *
   * @return Array<User>
   */
  students () {
    return this.belongsToMany('App/Models/User').pivotModel(
      'App/Models/UserClass'
    )
  }
}

module.exports = Class

On my method index() of controller:

  async index ({ request, response, view }) {
    const {
      page,
      class: class_id,
      course: course_id,
      teacher: teacher_id
    } = request.get()

    const classes = await Class.query()
      .orderBy('created_at', 'DESC')
      .with('teachers')
      .with('courses')
      .with('students')
      .withCount('teachers as total_teachers')
      .withCount('courses as total_courses')
      .withCount('students as total_students')
      .byClass(class_id)
      .byCourse(course_id)
      .byTeacher(teacher_id)
      .paginate(page)

    return classes
  }

And object received in response of request:

{
    "total": 2,
    "perPage": 20,
    "page": 1,
    "lastPage": 1,
    "data": [
        {
            "id": 15,
            "title": "The title",
            "description": "The class description",
            "created_at": "2018-08-09 01:47:22",
            "updated_at": "2018-08-09 01:47:22",
            "teachers": [
                {
                    "id": 8,
                    "username": "username",
                    "first_name": "first_name",
                    "last_name": "last_name",
                    "pivot": {
                        "user_id": 8,
                        "class_id": 15
                    }
                }
            ],
            "courses": [
                {
                    "id": 2,
                    "title": "Title",
                    "description": "The course description",
                    "created_at": "2018-08-09 00:52:40",
                    "updated_at": "2018-08-09 00:52:40",
                    "pivot": {
                        "course_id": 2,
                        "class_id": 15
                    }
                }
            ],
            "students": [
                {
                    "id": 9,
                    "username": "username",
                    "first_name": "first_name",
                    "last_name": "last_name",
                    "pivot": {
                        "user_id": 9,
                        "class_id": 15
                    }
                }
            ],
            "__meta__": {
                "total_teachers": 1,
                "total_courses": 1,
                "total_students": 1
            }
        }
    ]
}

I would like to hide the "pivot" object within the relationships in the objects "teachers", "students", "courses"...

If you have any questions, let me know! Thank you.

[thetutlage]

Ahh okay. I don't think it's possible right now. Within the pivot model you can set hidden fields user_id and class_id, but that will not remove the top level pivot key from the object.

I will add this to the enhancements and will try to work on it later

[Dysanix]

Just dropping by to show my support for this Enhancement-request.

[thetutlage]

The newer release of AdonisJs Lucid @adonisjs/[email protected] will exclude all pivot columns by default and one can add them by creating a computed property (if required).

Let's imagine, you want to include the pivot object along with the course id. It can be done as follows:

class Teacher extends Model {
  get pivot () {
    if (this.$extras.pivot_course_id) {
      return {
        course_id: this.$extras.pivot_course_id
      }
    }
  }
}

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