Tooltip overlay with cartodb createlayer

Question

I enabled a tooltip on my viz using the code below.

cartodb.createVis('map', vizUrl, {
    center_lat: 16.55,
    center_lon: -106.5,
    zoom: 6
})
    .done(function (vis, layers) {          
        spillLayer = layers[1];
    layers[1].getSubLayer(1).setInteraction(true);
        layers[1].getSubLayer(1).setInteractivity('v1');

        vis.addOverlay({
            layer: spillLayer,
            type: 'tooltip',
            template: '<p>{{v1}} gallons</p>'
        });

})

I am now in a situation where I need to load the viz after a L.Map has already been created. How would I enable the tooltip in this situation? When I run the code below I get an error like

cartodb.createLayer(map, vizUrl)
     .addTo(map)
     .done(function (vis, layer) {           

        spillLayer = layer[1];
        layers[1].getSubLayer(1).setInteraction(true);
        layers[1].getSubLayer(1).setInteractivity('v1');



        vis.addOverlay({
            layer: spillLayer,
            type: 'tooltip',
            template: '<p>{{v1}} gallons</p>'
        });

)}

Answer 1

I believe you are mixing up the createViz and createLayer methods. With createViz you get back a viz element, since it sets up the map etc for you, with createLayer you only get back a layers element. Change this line,

.done(function (vis, layer) {

to

.done(function (layer) {