Intense validations using yupjs

workingHours.ts

const workingHoursSchema = yup
  .object()
  .shape(
    {
      startHour: yup.number().when(["startMinute", "endHour", "endMinute"], {
        is: (...args: string[]) => args.reduce((acc, v) => !!v || acc, false as boolean), // really typescript :|
        then: yup
          .number()
          .integer()
          .min(0)
          .max(23)
          .required(),
        otherwise: yup
          .number()
          .integer()
          .min(0)
          .max(23)
      }),
      startMinute: yup.number().when(["startHour", "endHour", "endMinute"], {
        is: (...args: string[]) => args.reduce((acc, v) => !!v || acc, false as boolean),
        then: yup
          .number()
          .integer()
          .min(0)
          .max(59)
          .required(),
        otherwise: yup
          .number()
          .integer()
          .min(0)
          .max(59)
      }),
      endHour: yup.number().when(["startHour", "startMinute", "endMinute"], {
        is: (...args: string[]) => args.reduce((acc, v) => !!v || acc, false as boolean),
        then: yup
          .number()
          .integer()
          .min(0)
          .max(23)
          .required(),
        otherwise: yup
          .number()
          .integer()
          .min(0)
          .max(23)
      }),
      endMinute: yup.number().when(["startHour", "startMinute", "endHour"], {
        is: (...args: string[]) => args.reduce((acc, v) => !!v || acc, false as boolean),
        then: yup
          .number()
          .integer()
          .min(0)
          .max(59)
          .required(),
        otherwise: yup
          .number()
          .integer()
          .min(0)
          .max(59)
      })
    },
    [
      // for more info on these: https://github.com/jquense/yup/issues/176#issuecomment-369925782
      ["startHour", "startMinute"],
      ["startHour", "endHour"],
      ["startHour", "endMinute"],
      ["startMinute", "endHour"],
      ["startMinute", "endMinute"],
      ["endHour", "endMinute"]
    ]
  )
  .test("validate-working-hours", "Start of working hours should be smaller than end", function(val) {
    const workingHours = Object.values(val);
    // when there are no more non-numeric values for working hours, validate end time > start time
    if (workingHours.length && !workingHours.filter(v => typeof v !== "number" || Number.isNaN(v)).length) {
      const startTime = Number.parseInt(`${val.startHour}${val.startMinute.toString().padEnd(2, "0")}`, 10);
      const endTime = Number.parseInt(`${val.endHour}${val.endMinute.toString().padEnd(2, "0")}`, 10);

      return startTime < endTime;
    }

    return true;
  })
  // this transform lets the default `initialWorkingHours` value
  // which contains strings instead of numbers
  // (cuz react, see comment near initialWorkingHours)
  .transform((v, ov) => {
    if (!Object.values(ov).filter(val => val !== "").length) {
      return {};
    }
    return v;
  });