Custom basemaps in basemap gallery

Question

I've added my custom basemap to my basemap gallery but can't figure out how to add other basemaps.

var customBMs = new LocalBasemapsSource(
 {
 basemaps:[
    bm, 
    Basemap.fromId("OS Open Background"),
    Basemap.fromId("OS Open Carto"),
    Basemap.fromId("OS Open Grey Labels"),
    Basemap.fromId("OS Open Grey"),
    Basemap.fromId("OS Open Rasters")
 ]
 }
 );

var basemapGallery = new BasemapGallery({
 view: view,
 source:customBMs
 });

What id do I use for the OS Open maps? I've tried portal ids with no luck

ShakilChoudhury · Accepted Answer

Got it to work by just pushing to the existing basemapGallery.source.basemaps.items array instead of providing a new one