function validTime(str) {
    let formatCheck = /\d{2}:\d{2}/;
    let splitted = str.split(":");
    let left = parseInt(splitted[0]);
    let right = parseInt(splitted[1]);
    
    // Check for HH:MM format
    if (str.match(formatCheck) === null) {
        alert("Please provide time in format 'HH:MM'");
    }
    
    // Verify time is valid
    if ((left >= 00 && left <= 24) && (right >= 00 && right <= 59)) {
        return true
    } else {
        return false
    }
}



/**
* 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);
    });
});