How can I get a nested object within lokijs Collection

Question

I'm using lokijs to store some data that I will need to work with. My data is shown below. As a newbie to lokijs I've been struggling to find a way to get item_part_option_groupsarray out of part.

My code

        partDb = new loki('part.json');
        partData =  partDb.addCollection('part');
        $.get(urlHelper.createUrl('item/parts', 'part', config.partId + '.json'), function(data){
           partData.insert(data);
            var data = partData.find({'part':'item_part_option_groups'});
            console.log(data);
        });

The Data

   {
        "part": {
            "item_part_id": 10,
            "name": "Sleeve",
            "has_validation": 0,
            "description": "",
            "is_disabled": "1",
            "created": "2015-07-22T23:55:09+0000",
            "updated": null,
            "item_part_option_groups": [{
                "item_part_option_group_id": 10,
                "order_index": 0,
                "description": "",
                "item_part_id": 10,
                "created": "2015-07-22T23:55:39+0000",
                "updated": null,
                "item_part_options": [{
                    "item_part_option_id": 8,
                    "name": "Sleeve Type",
                    "is_conform_value": 0,
                    "has_validation": 1,
                    "item_part_option_type_id": 3,
                    "created": "2015-07-22T23:57:24+0000",
                    "updated": null,
                    "item_part_option_values": [{
                        "value": "Short Sleeve",
                        "order_index": 0,
                        "item_part_option_id": 8,
                        "item_part_option_value_id": 7,
                        "item_part_option_includes": [

                        ]
                    }, {
                        "value": "Long Sleeve",
                        "order_index": 0,
                        "item_part_option_id": 8,
                        "item_part_option_value_id": 8,
                        "item_part_option_includes": [

                        ]
                    }, ]
                }]
            }]
        }

    }

Answer 1

if I understand correctly, you're over-complicating your life. LokiJS will add some properties to your object (like the id $loki and a meta object) but basically it will return a reference to this slightly modified original object (unless you're using the clone option when constructing the collection).

This means that - to log item_part_option_groups - you only need to do:

console.log(data.item_part_option_groups)

The query your wrote in find will look for an object in the partData collection whose part property equals to item_part_option_groups. Obviously that's not what you want. Once the object is in the collection - which happens here:

partData.insert(data)

The record is a plain js object, so if you change it to:

var record = partData.insert(data)

you simply need to refer to record['item_part_option_groups'] to grab the property you want. All this has little to do with LokiJS however: it seems to me as if you're trying to obtain a "partial" object, which can only be done with a map-reduce or other more complex transforms.