Your forgot the square brackets. The object has to be in an array.
mapView.ui.add([{
component: home,
position: "bottom-right",
index: 0
}, {
component: zoom,
position: "bottom-right",
index: 1
}, {
component: searchWidget,
position: "top-right"
}, {
component: scaleBar,
position: "bottom-left"
}]);