function createMap(mapJson){const map=new Map();for(const entry of mapJson){if(entry.id===undefined){throw new Error('Missing required key "id" in streaming event.');}
map.set(entry.id,entry);}
return map;}
function createMaps(mapsJson){const maps=new Map();for(const[name,mapJson]of Object.entries(mapsJson)){maps.set(name,createMap(mapJson));}
return maps;}