[
{
    "_id": "5a61acfdd5df1761dd2eb1ef",
    "branch": "Lucena City",
    "__v": 0,
    "building": [
        {
            "name": "mhq",
            "floors": [
                "1st",
                "2nd",
                "3rd"
            ]
        }
    ],
    "dateCreated": "2018-01-19T08:31:57.121Z"
},
{
    "_id": "5a61ad6fd5df1761dd2eb1f1",
    "branch": "Lucban",
    "__v": 0,
    "building": [
        {
            "name": "mhq",
            "floors": [
                "ground floor",
                "2nd floor",
                "3rd floor",
                "4th floor",
                "5th floor"
            ]
        }
    ],
    "dateCreated": "2018-01-19T08:33:51.761Z"
},
{
    "_id": "5a61ada1d5df1761dd2eb1f2",
    "branch": "loperz",
    "__v": 0,
    "building": [
        {
            "name": "lope",
            "floors": [
                "ground floor",
                "1st floor"
            ]
        }
    ],
    "dateCreated": "2018-01-19T08:34:41.904Z"
}]

<div class="row justify-content-md-center">
<div class="col-md-4">
    <label for="branch">
        <strong>Branch</strong>
    </label>
    <select ng-options="loc as loc.branch for loc in vm.locations" ng-model="vm.locationTest" class="form-control">
    </select>
    <small id="emailHelp" class="form-text text-muted">Select branch.</small>
</div>
<div class="col-md-4">
    <label for="building">
        <strong>Building</strong>
    </label>
    <select ng-options="ds as ds.building for ds in vm.locationTest" ng-model="vm.roomData.building" class="form-control">
    </select>
</div>
<div class="col-md-4">
    <label for="roomFloor">
        <strong>Room Floor</strong>
    </label>
    <select ng-options="ds as ds for ds in vm.locationTest.floors" ng-model="vm.roomData.roomFloor" class="form-control">
    </select>
</div>