여러 뎁스의 reference 에 대하여 populate 하기

https://mongoosejs.com/docs/populate.html

Mongoose v8.3.5: Query Population

 

 

https://stackoverflow.com/questions/63764135/mongoose-how-to-populate-across-multiple-levels-and-use-field-selection-in-the

Mongoose: How to populate across multiple levels and use field selection in the same time?

const ProfileSchema = new Schema({
  //We want to associate the user with the profile
  user: {
    //This will associate the user by his id
    type: Schema.Types.ObjectId,
    ref: "users",
  },
  // We want a user friendly url
  handle: {
    type: String,
    // required: true, // Even though we are doing pre-validatioon
    max: 40,
  },
  bio: {
    type: String,
  },
  school: {
    type: String,
  },
  major: {
    type: String,
  },
  website: {
    type: String,
  },
  location: {
    type: String,
  },
  // Optional (might add it later)
  /**
   *   status: {
    //where they are in their career
    type: String,
    required: true
  },
   */
  skills: {
    // In the form they will put skill1,skill2,.. and we will turn that into an array
    type: [String],
    // required: true,
  },
  interests: {
    // In the form they will put interest1,interest2,.. and we will turn that into an array
    type: [String],
    // required: true,
  },
  help_offers: {
    // In the form they will put help_offer1,help_offer2,.. and we will turn that into an array
    type: [String],
    // required: true,
  },
  // Might be volunteering experience
  experience: [
    {
      title: { type: String, required: true },
      company: {
        type: String,
        required: true,
      },
      location: {
        type: String,
      },
      from: {
        type: Date,
        required: true,
      },
      to: {
        type: Date,
        // Not required, going to be a checkbox
      },
      current: {
        type: Boolean,
        default: false,
      },
      description: {
        type: String,
      },
    },
  ],
  education: [
    {
      school: { type: String, required: true },
      degree: {
        type: String,
        required: true,
      },
      fieldofstudy: {
        type: String,
        required: true,
      },
      from: {
        type: Date,
        required: true,
      },
      to: {
        type: Date,
        // Not required, going to be a checkbox
      },
      current: {
        type: Boolean,
        default: false,
      },
      description: {
        type: String,
      },
    },
  ],
  social: {
    youtube: {
      type: String,
    },
    twitter: {
      type: String,
    },
    facebook: {
      type: String,
    },
    linkedin: {
      type: String,
    },
    instagram: {
      type: String,
    },
  },
  date: {
    type: Date,
    dafault: Date.now,
  },
  videoURL: {
    type: String,
  },
});

const UserSchema = new Schema({
  name: {
    type: String,
    required: true,
  },
  surname: {
    type: String,
    required: true,
  },
  email: {
    type: String,
    required: true,
  },
  password: {
    type: String,
    required: true,
  },
 avatar: {
    type: String,
  },
  birthday: {
    type: String,
    required: true,
  },
  country: {
    type: String,
    required: true,
  },
  date: {
    type: Date,
    default: Date.now,
  },
  following: [
    {
      type: Schema.Types.ObjectId,
      //The User has only ObjectId in uses array. ref helps us get full fields of User when we call populate() method.
      //https://bezkoder.com/mongodb-many-to-many-mongoose/
      ref: "users",
    },
  ],
  followers: [
    {
      type: Schema.Types.ObjectId,
      ref: "users",
    },
  ],
});

Profile.findOne({ user: req.user.id })
    .populate({
        path: ["user", ["name", "avatar"]],
        populate: { path: "following" },

user 의 name, avatar 필드를 populate 하고 following 필드는 다시 populate 한다. 

https://stackoverflow.com/questions/62607128/mongoose-populate-multiple-levels

Mongoose populate multiple levels