Convert seconds to HH-MM-SS with JavaScript?

Question

How can I convert seconds to an HH-MM-SS string using JavaScript?

Answer 1

For the special case of HH:MM:SS.MS (eq: "00:04:33.637") as used by FFMPEG to specify milliseconds.

[-][HH:]MM:SS[.m...]

HH expresses the number of hours, MM the number of minutes for a maximum of 2 digits, and SS the number of seconds for a maximum of 2 digits. The m at the end expresses decimal value for SS.

/* HH:MM:SS.MS to (FLOAT)seconds ---------------*/
function timerToSec(timer){
   let vtimer = timer.split(":")
   let vhours = +vtimer[0]
   let vminutes = +vtimer[1]
   let vseconds = parseFloat(vtimer[2])
   return vhours * 3600 + vminutes * 60 + vseconds
}

/* Seconds to (STRING)HH:MM:SS.MS --------------*/
function secToTimer(sec){
  let o = new Date(0)
  let p =  new Date(sec*1000)  
  return new Date(p.getTime()-o.getTime())
    .toISOString()
    .split("T")[1]
    .split("Z")[0]
}

/* Example: 7hours, 4 minutes, 33 seconds and 637 milliseconds */
const t = "07:04:33.637"
console.log(
  t + " => " +
  timerToSec(t) +
  "s"
)

/* Test: 25473 seconds and 637 milliseconds */
const s = 25473.637 // "25473.637"
console.log(
  s + "s => " + 
  secToTimer(s)
)

Example usage, a milliseconds transport timer:

/* Seconds to (STRING)HH:MM:SS.MS --------------*/
function secToTimer(sec){
  let o = new Date(0)
  let p =  new Date(sec*1000)  
  return new Date(p.getTime()-o.getTime())
    .toISOString()
    .split("T")[1]
    .split("Z")[0]
}

let job, origin = new Date().getTime()
const timer = () => {
  job = requestAnimationFrame(timer)
  OUT.textContent = secToTimer((new Date().getTime() - origin) / 1000)
}

requestAnimationFrame(timer)

span {font-size:4rem}

RESET
RESTART
STOP

Example usage, binded to a media element

/* Seconds to (STRING)HH:MM:SS.MS --------------*/
function secToTimer(sec){
  let o = new Date(0)
  let p =  new Date(sec*1000)  
  return new Date(p.getTime()-o.getTime())
    .toISOString()
    .split("T")[1]
    .split("Z")[0]
}

VIDEO.addEventListener("timeupdate", function(e){
  OUT.textContent = secToTimer(e.target.currentTime)
}, false)

span {font-size:4rem}

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Outside the question, those functions written in php: