There is no local income tax in New Jersey. Boxes 18, 19, and 20 on your W-2 should be blank. Leave those boxes empty in TurboTax.
Some New Jersey employers put FLI in box 19. It doesn't belong there. It belongs in box 14. Enter FLI in box 14 in TurboTax. Leave boxes 18, 19, and 20 empty.