Further improve on config() type#138

Merged

laurenzlong merged 3 commits intofirebase:masterfrom

Nov 30, 2017

Commits on Nov 30, 2017

Update config().firebase typings to not be undefined since error will be thrown if it is undefined.
bmass02
committed
Added type guard when testing for existence of 'firebase' in merged.
bmass02
committed
Updated to use existing type.
bmass02
committed