Cannot get subscription event to fire

export const catFactsRouter = createTRPCRouter({
  fact: publicProcedure.query(({ ctx }) => {

    const fact = ctx.prisma.catFact.findFirst({
      orderBy: {
        createdAt: "desc",
      },
    });

    return fact;
  }),
  addFact: protectedProcedure
    .input(
      z.object({
        token: z.string().min(1),
        fact: z.string().min(1)
      })
    )
    .mutation(async ({ input, ctx }) => {
      console.log(`protectedProcedure.mutation()`);
      const fact = await ctx.prisma.catFact.create({
        data: {
          fact: input.fact,
        }
      });
      console.log(`ctx.ee.emit(Events.NEW_CAT_FACT, fact)`);
      ctx.ee.emit(Events.NEW_CAT_FACT, fact);
      console.log(`ee.emit(Events.NEW_CAT_FACT, fact);`);
      return fact;
    }),
  onFact: publicProcedure.subscription(({ ctx }) => {
    console.log("publicProcedure.subscription")

    // `resolve()` is triggered for each client when they start subscribing `onFact`
    // return an `observable` with a callback which is triggered immediately
    return observable<CatFact>((emit) => {
      const onCatFact = (data: CatFact) => {
        console.log(`Emitting fact to client:`, data);
        // emit data to client
        emit.next(data);
      };
      console.log("ctx.ee.on(Events.NEW_CAT_FACT, onCatFact);")

      ctx.ee.on(Events.NEW_CAT_FACT, onCatFact);

      return () => {
        ctx.ee.off(Events.NEW_CAT_FACT, onCatFact);
      };
    });
  }),
});