timeConversion.js

function timeConversion(stringg){
    let hour = stringg.substring(0,2)
    let mins = stringg.substring(3,5)
    let seconds = stringg.substring(6,8)
    let timeconvention = stringg.substring(8,10)
    let rest = stringg.substring(2,8)

    if(timeconvention == 'PM'){
        if(parseInt(hour) != 12){
            let hour1 = 0
            hour1 = parseInt(hour) + 12
            console.log(hour1.toString() + rest)
            return hour1.toString() + rest
        }
        else{
            console.log(hour + rest)
            return hour + rest
        }
                
    }
    else if(timeconvention == 'AM'){
        if(parseInt(hour) != 12){
            console.log(hour + rest)
            return hour + rest

        }
        else{
            console.log('00'+rest)
            return '00'+rest
        }
                
    }

}

timeConversion('12:05:45AM')
timeConversion('02:05:30PM')
timeConversion('08:05:25AM')