code: function getEngine(name) {
              if (!dbconfig.has(name)) {
                  d.fatal("Trying to access data storage that is not configured:", name);
              }
              var conf = dbconfig.get(name);
              if (!conf.engine) {
                  conf.engine = engine(conf.url);
              }
              return conf.engine;
          }
docs: Helper function to instantiate and initialize engine.
  If the named engine is not yet set in `dbconfig`, it is
  created and inserted there. Note that every time `dbconfig`
  is changed, the engine is nullified and new one is instantiated
  on the first use.