Filtered subcollections expose parent collection items

[ahamid]

It appears that (at least for Memory store) filtering produces sub-collections that expose (excluded) parent items. Memory.getSync explicitly retrieves items from storage.fullData, so I wonder if this is by design for some reason:

getSync: function (id) {
    return this.storage.fullData[this.storage.index[id]];
},

var all = new Memory({data:[{id:1, c: 'all'}, {id:2, c: 'subset'}]})
var subset = all.filter({c: 'subset'})
subset.fetchSync() // [{id:2, c: 'subset'}]
subset.data        // [{id:2, c: 'subset'}]
subset.get(1)      // {id:1, c: 'all'}, I would expect null/undefined here

Hypothetically Memory could consult data instead of this.storage.fullData however it appears that lookup is based on an position index maintained against the fullData, so doing so would require keeping a per-sub-collection index for lookups (or changing how indexing/lookup is implemented).