Restore pre 5.1.1 behavior and fix types (#759)

* Restore pre 5.1.1 behavior and fix types

* Update types

* Move tokenGetter back to optional parameter

* Add tsd tests and fix types

* Add additional tests and run on CI

* Add additional tests around tokenGetter usage

Author: frederikprijck

.circleci/config.yml

@@ -16,6 +16,7 @@ jobs:
       - run: npm run lint
       - run: npm run build
       - run: npm run test:ci
+      - run: npm run test:types
       - codecov/upload
 workflows:
   build_and_test: