function validTime(str) {
  if (typeof str !== "string" || !str.includes(":")) {
    return false;
  }
  let [hour, minutes] = str.trim().split(":");
  hour = hour.trim();
  minutes = minutes.trim();
  if (/\D/.test(hour) || /\D/.test(minutes)) {
    return false;
  }
  hour = parseInt(hour);
  minutes = parseInt(minutes);
  return 0 <= hour && hour < 24 && 0 <= minutes && minutes < 60;
}




/**
* Test Suite 
*/
describe('validTime()', () => {
    it('returns true for valid time', () => {
        // arrange
        const str = '13:58';
        
        // act
        const result = validTime(str);

        // log
        console.log("result 1: ", result);
        
        // assert
        expect(result).toBe(true);
    });

    it('returns false when invalid hours', () => {
        // arrange
        const str = '25:51';
        
        // act
        const result = validTime(str);

        // log
        console.log("result 1: ", result);
        
        // assert
        expect(result).toBe(false);
    });

    it('returns false when invalid minutes', () => {
        // arrange
        const str = '02:76';
        
        // act
        const result = validTime(str);

        // log
        console.log("result 1: ", result);
        
        // assert
        expect(result).toBe(false);
    });
});