function readAll() {
    var objectStore = db.transaction("employee").objectStore("employee");
    
    objectStore.openCursor().onsuccess = function(event) {
       var cursor = event.target.result;
       
       if (cursor) {
          alert("Name for id " + cursor.key + ", Value: " + cursor.value);
          cursor.continue();
       } else {
          alert("No more entries!");
       }
    };
 }

	var ReadAll js.Func
	ReadAll = js.FuncOf(func(this js.Value, args []js.Value) interface{} {
		defer ReadAll.Release()
		cursor := this.Get("result")
		if cursor {
				_ = cursor.Get("key")
				value := cursor.Get("value")
				Window.Call("alert", value)
				cursor.Call("continue")
			} else {
				Window.Call("alert", "No more records")
			} 
		return nil
	})
	db.ObjectStore.Call("openCursor").Set("onsuccess", ReadAll)

non-bool cursor (type js.Value) used as if condition

if cursor.Truthy() {
  ...
}

if !cursor.Truthy() {
  ...
}