Recursive Functions Return Type in TypeScript

 const recursiveFunc = async (params: {
        db: PlanetScaleDatabase<Schema>
        // unknown for demo purpose
        data?: ReadonlyArray<unknown>
        offSet?: number
        pageSize?: number
      }) => {
        const { db, data = [], offSet = 0, pageSize = 100000 } = params

        // the query is where we get the data
        const dataQuery = await db
          .select()
          .from(mySqlTable)
          .offset(offSet)
          .limit(pageSize)

        // we save the data by passing the data back into itself
        const dataSave = pipe(data, ReadonlyArray.appendAll(dataQuery))

        return pipe(
          ReadonlyArray.length(dataQuery) < pageSize,
          Boolean.match({
            onFalse: () =>
              // if we dont have all the records run it again with new offset
              recursion({
                db,
                data: dataSave,
                offSet: ReadonlyArray.length(dataSave),
              }),
            // returns when we have all the records from the db
            onTrue: () => dataSave,
          }),
        )
      }