Unintuitively, informal speaking often skips the ne but the pas is mandatory. Je mange pas ça - I don’t eat this. Also the second part can add nuance to the n

Unintuitively, informal speaking often skips the ne but the pas is mandatory. Je mange pas ça - I don’t eat this. Also the second part can add nuance to the negation, fe. Je ne mange plus ça - I don’t eat this anymore. *Not a native speaker so there’s definitely more to it than I know.