card-validator/src/__tests__/lib/parse-date.ts

A library for validating credit card fields

import { parseDate, MonthAndYear } from "../../lib/parse-date";

describe("parse-date", () => {
  describe.each([
    [
      "with empty month and empty year",
      [
        ["", { month: "", year: "" }],
        [" ", { month: "", year: "" }],
        ["/", { month: "", year: "" }],
      ],
    ],
    [
      "with deliminators",
      [
        ["12 21", { month: "12", year: "21" }],
        ["12 / 21", { month: "12", year: "21" }],
        ["12/21", { month: "12", year: "21" }],
        ["2020-10", { month: "10", year: "2020" }],
      ],
    ],
    [
      'when the datestrings starts with "0"',
      [
        ["0", { month: "0", year: "" }],
        ["01", { month: "01", year: "" }],
        ["052", { month: "05", year: "2" }],
        ["0529", { month: "05", year: "29" }],
        ["052900", { month: "05", year: "2900" }],
      ],
    ],
    [
      'when the datestrings starts with "2-9"',
      [
        ["2", { month: "2", year: "" }],
        ["31", { month: "3", year: "1" }],
        ["452", { month: "4", year: "52" }],
        ["8529", { month: "8", year: "529" }],
        ["952900", { month: "9", year: "52900" }],
      ],
    ],
    [
      "when the datestring starts with 13-19",
      [
        ["13", { month: "1", year: "3" }],
        ["145", { month: "1", year: "45" }],
        ["1580", { month: "1", year: "580" }],
        ["16701", { month: "1", year: "6701" }],
        ["17701", { month: "1", year: "7701" }],
        ["18701", { month: "1", year: "8701" }],
        ["19701", { month: "1", year: "9701" }],
      ],
    ],
    [
      "when the datestring has exactly 5 characters",
      [
        ["52019", { month: "5", year: "2019" }],
        ["39876", { month: "3", year: "9876" }],
      ],
    ],
    [
      "when the datestring is greater than 5 characters",
      [
        ["122039", { month: "12", year: "2039" }],
        ["108760", { month: "10", year: "8760" }],
        ["1187601234", { month: "11", year: "87601234" }],
        ["520190", { month: "5", year: "20190" }],
        ["398760", { month: "3", year: "98760" }],
      ],
    ],
  ] as Array<[string, Array<[string, MonthAndYear]>]>)(
    "%s",
    (description, tests) => {
      it.each(tests)("parses %s to be %p", (parseMe, meta) => {
        expect(parseDate(parseMe)).toEqual(meta);
      });
    },
  );

  describe("datestrings starting with 10-12", () => {
    let savedDateObject: DateConstructor;

    beforeEach(() => {
      savedDateObject = Date;
      /*
       *  because there's some internal logic to whether or not an
       *  expiration date is potentially valid, we must freeze time at
       *  the year 2019 for these tests to keep working once the year is
       *  over
       *  */
      const fixedDate = new Date(2019, 9);

      // eslint-disable-next-line @typescript-eslint/no-explicit-any
      window.Date = jest.fn().mockImplementation(() => fixedDate) as any;
    });

    afterEach(() => {
      window.Date = savedDateObject;
    });

    it("parses month with 2 digits when it starts with 1 and the remaining year is not potentially valid", () => {
      expect(parseDate("100")).toEqual({ month: "10", year: "0" });
      expect(parseDate("104")).toEqual({ month: "10", year: "4" });
      expect(parseDate("109")).toEqual({ month: "10", year: "9" });
      expect(parseDate("110")).toEqual({ month: "11", year: "0" });
      expect(parseDate("115")).toEqual({ month: "11", year: "5" });
      expect(parseDate("118")).toEqual({ month: "11", year: "8" });
    });

    it("parses month with 1 digit when it starts with 1 and the remaining year is potentially valid", () => {
      expect(parseDate("119")).toEqual({ month: "1", year: "19" });
      expect(parseDate("120")).toEqual({ month: "1", year: "20" });
      expect(parseDate("125")).toEqual({ month: "1", year: "25" });
      expect(parseDate("129")).toEqual({ month: "1", year: "29" });
    });
  });
});