toJSON() not working for level 3 inclusions

[erikverheij]

I'm using the toJSON() method so I can apply lodash methods like _.omit() on the data. In can only get it working until the second inclusion level.

var filter  = { include: {games: 'results'}};
app.models.Challenger.find(filter, function(err, challengers) {
  var challengers = challengers.toJSON();
  console.log(challengers[0].games[0].results[0]);
  // --> Properties of result are only available via the __data property
});

When challengers is returned as HTTP response body the data is returned as expected. Is loopback using a different method than .toJSON() to serialize the data returned to the client?

[raymondfeng]

Serialization calls .toJSON() recursively as part of JSON.stringify(). There seems to be an issue that in the toJSON() implementation which doesn't go into the 3rd level. We'll investigate.

[raymondfeng]

It seems to be a user error:

var filter  = { include: {games: 'results'}};
app.models.Challenger.find(filter, function(err, challengers) {
  // Please note challengers is an array, Array.toJSON() doesn't recursively convert all child objects
  var challengers = challengers.toJSON();
  console.log(challengers[0].games[0].results[0]);
  // --> Properties of result are only available via the __data property
});

[erikverheij]

Ah, that was a typo :( I'll make a test spec to reproduce the issue.

[erikverheij]

This mocha test reproduces the issue;

var q = require('q');
var loopback = require('loopback');
var app = require('../server');
var assert = require('assert');
var async = require('async');
var _ = require('lodash');


function createSchema() {

  app.dataSource('db', {
    connector: 'memory'
  });

  var ChallengerModel = loopback.createModel(
    {
      name: 'Challenger',
      base: 'PersistedModel',
      properties: {
        name: {
          type: 'string',
        }
      },
      relations: {
        gameParticipations: {
          type: 'hasMany',
          model: 'GameParticipation',
          foreignKey: ''
        }
      }
    }
  );
  var GameParticipationModel = loopback.createModel(
    {
      name: 'GameParticipation',
      base: 'PersistedModel',
      properties: {
        date: {
          type: 'date',
        }
      },
      relations: {
        challenger: {
          type: 'belongsTo',
          model: 'Challenger',
          foreignKey: ''
        },
        results: {
          type: 'hasMany',
          model: 'Result',
          foreignKey: ''
        }
      }
    }
  );
  var ResultModel = loopback.createModel({
    name: 'Result',
    base: 'PersistedModel',
    properties: {
      points: {
        type: 'number',
      }
    },
    relations: {
      gameParticipation: {
        type: 'belongsTo',
        model: 'GameParticipation',
        foreignKey: ''
      }
    }
  });

  app.model(ChallengerModel, { dataSource: 'db' });
  app.model(GameParticipationModel, { dataSource: 'db' });
  app.model(ResultModel, { dataSource: 'db' });

}

function createChallengers(callback){
  app.models.Challenger.create([{name: 'challenger1'}, {name: 'challenger2'}], callback);
}

function createGameParticipations(challengers, callback){
  app.models.GameParticipation.create([
    { challengerId: challengers[0].id, date: Date.now() },
    { challengerId: challengers[0].id, date: Date.now() }
  ], callback);
}

function createResults(gameParticipations, callback){
  app.models.Result.create([
    { gameParticipationId: gameParticipations[0].id, points: 10 },
    { gameParticipationId: gameParticipations[0].id, points: 20 }
  ], callback);
}


before(function importSampleData(done) {

  createSchema();

  async.waterfall([
    createChallengers,
    createGameParticipations,
    createResults,
    function(){ done(); }
  ]);

});


describe('ModelBaseClass.toJSON()', function() {
  it('should recursively serialize objects', function(done) {
    var filter  = { include: { gameParticipations: 'results'} };
    app.models.Challenger.find(filter, function(err, challengers) {

      var levelOneInclusion = challengers[0].toJSON().gameParticipations[0];
      assert(_.isUndefined(levelOneInclusion.__data), '.__data of a level 1 inclusion is undefined.');

      var levelTwoInclusion = challengers[0].toJSON().gameParticipations[0].results[0];
      assert(_.isUndefined(levelTwoInclusion.__data), '__data of a level 2 inclusion is undefined.');
      done();
    });
  });
});

[ritch]

@erikverheij thanks for the test case :)

[superkhau]

@raymondfeng Can I close this?

[bajtos]

The issue should have been fixed by loopbackio/loopback-datasource-juggler#600. Please open a new issue if the problem still persists.