SOURCE

let a = new Date().getTime()
// console.log(a)
let b = 30
let c = 8
let e = 4
for (var i=1;i<=b;i++)
{ 
//    console.log(a-(i*60))
// getData(a-(i*60000))
   
}
for (var i=1;i<=c;i++)
{ 
//    console.log(a-(i*60))
// getData(a-(i*3600000))
   
}
for (var i=1;i<=e;i++)
{ 
//    console.log(a-(i*60))
getData(a-(i*3600000))
   
}

function getData(n) {
  let now = new Date(n),
    y = now.getFullYear(),
    m = now.getMonth() + 1,
    d = now.getDate();
    h = now.getHours()+1;
    f = now.getMinutes()+1
    mm = now.getSeconds()+1
  console.log(y + "-" + (m < 10 ? "0" + m : m) + "-" + (d < 10 ? "0" + d : d) + " " + (h<10?"0"+h:h)+":"+(f<10?"0"+f:f)+":"+(mm<10?"0"+mm:mm)) 
}