30-seconds-of-code/snippets/formatDuration.md

formatDuration

Returns the human readable format of the given number of milliseconds.

Divide ms with the appropriate values to obtain the appropriate values for day, hour, minute, second and millisecond. Use Object.entries() with Array.filter() to keep only non-zero values. Use Array.map() to create the string for each value, pluralizing appropriately. Use String.join(', ') to combine the values into a string.

const formatDuration = ms => {
  if (ms < 0) ms = -ms;
  const time = {
    day: Math.floor(ms / 86400000),
    hour: Math.floor(ms / 3600000) % 24,
    minute: Math.floor(ms / 60000) % 60,
    second: Math.floor(ms / 1000) % 60,
    millisecond: Math.floor(ms) % 1000
  };
  return Object.entries(time)
    .filter(val => val[1] !== 0)
    .map(val => val[1] + ' ' + (val[1] !== 1 ? val[0] + 's' : val[0]))
    .join(', ');
};

formatDuration(1001); // "1 second, 1 millisecond"
formatDuration(343250555); // "3 days, 23 hours, 20 minutes, 50 seconds, 555 milliseconds"
formatDuration(34325055574); // "397 days, 6 hours, 44 minutes, 15 seconds, 574 milliseconds"