How to add commas and "and" at the right place

Question

Input: seconds, Output: grammatically correct, formatted time (with words spelled out).

So far I managed to get as far as going from say 40044373 to 1 year, 98 days, 5 hours, 37 minutes, 1 second - note the correct plurals and commas.

What I'm missing is an "and" that is added instead of the last comma (of course only when there's enough inputs). For example 1 year and 1 second for input 31556953 instead of my current 1 year, 1 second in that case.

function formatDuration (seconds) {

var numyears = Math.floor(seconds / 31556952);
if (numyears > 1) {var pluryears = " years, "} else {var pluryears = " year, "};
if (numyears > 0) {var printyears = numyears + pluryears;} else {var printyears = ''};

var numdays = Math.floor((seconds % 31556952) / 86400);
if (numdays > 1) {var plurdays = " days, "} else {var plurdays = " day, "};
if (numdays > 0) {var printdays = numdays + plurdays;} else {var printdays = ''};

var numhours = Math.floor(((seconds % 31556952) % 86400) / 3600);
if (numhours > 1) {var plurhours = " hours, "} else {var plurhours = " hour, "};
if (numhours > 0) {var printhours = numhours + plurhours;} else {var printhours = ''};

var numminutes = Math.floor((((seconds % 31556952) % 86400) % 3600) / 60);
if (numminutes > 1) {var plurminutes = " minutes, "} else {var plurminutes = " minute, "};
if (numminutes > 0) {var printminutes = numminutes + plurminutes;} else {var printminutes = ''};

var numseconds = (((seconds % 31556952) % 86400) % 3600) % 60;
if (numseconds > 1) {var plurseconds = " seconds"} else {var plurseconds = " second"};
if (numseconds > 0) {var printseconds = numseconds + plurseconds;} else {var printseconds = ''};

return(printyears + printdays + printhours + printminutes + printseconds)
}

formatDuration(31556953);

Answer 1

A bit more compact solution that outputs the time string as intended:

function formatDuration (seconds) {
  var values = {
    years: Math.floor(seconds / 31556952),
    days: Math.floor((seconds % 31556952) / 86400),
    hours: Math.floor(((seconds % 31556952) % 86400) / 3600),
    minutes: Math.floor((((seconds % 31556952) % 86400) % 3600) / 60),
    seconds: (((seconds % 31556952) % 86400) % 3600) % 60,
  };
  var withUnits = Object.keys(values)
  .filter(function(unit) { return values[unit] > 0; })
  .map(function (unit) {
    var value = values[unit];
    return value + ' ' + (value === 1 ? unit.slice(0, -1) : unit);
  });
  return (withUnits.length > 1 ? withUnits.slice(0, -1).join(', ') + ' and ' : '') + withUnits.pop();
}

console.log(formatDuration(40044373));

Answer 2

Just a little regex that replaces the last comma:

return (printyears + printdays + printhours + printminutes + printseconds)
    .replace(/, (.*)$/, " and $1");

Answer 3

Unrelated, but the code as presented is pretty difficult to think about.

I'd extract the pluralization bit into its own method, roughly:

function pluralize(dur, s) {
  var ret = false;

  if (dur > 0) {
    ret = dur + ' ' + s;

    if (dur > 1) {
      ret += 's';
    }
  }

  return ret;
}

Then the mainline code, instead of doing everything manually, push onto an array, e.g.,

function formatDuration(seconds) {
  var segments = [];

  var years  = Math.floor(seconds / 31556952)
    , sYears = pluralize(years, 'year')
    ;

  if (sYears) { 
    segments.push(sYears); 
  }

  // etc.

You only need to special-case the seconds value:

  var seconds = (((seconds % 31556952) % 86400) % 3600) % 60
    , sSeconds = pluralize(seconds, 'second')
    ;

  var tmp = segments.join(', ');
  if (!sSeconds) {
    return tmp;
  }

  return tmp + ' and ' + sSeconds;
}

This could be cleaned up a little further, but produces output like the following:

1 year, 2 hours, 46 minutes and 43 seconds
1 year and 3 seconds

(Although I prefer Oxford Commas.)

Things I'd still do:

• Stop re-computing everything; keep a count of the number of seconds remaining.
• Pass the array into the function and avoid manual labor in the mainline code.
  • (Or wrap that up some other way.)

https://gist.github.com/davelnewton/a1371867527c5f1530498e1555e2fb0a

Answer 4

I wrote a small library for precisely this purpose:

https://github.com/adamshaylor/compound-subject

In your case, you’d use it like:

var formattedTimeString = compoundSubject([
    numyears + 'years',
    numdays + 'days',
    numhours + 'hours',
    numminutes + 'minutes',
    numseconds + 'seconds'
]).make();

Yielding something like:

2 years, 5 days, 3 hours, 10 minutes and 2 seconds

You can also add an Oxford comma by calling delimitAll().

Answer 5

You just need to add the 'and' in your return.

return(printyears + printdays + printhours + printminutes + 'and' + printseconds)

And remove the comma after the 'minute, ' on this line

if (numminutes > 1) {var plurminutes = " minutes "} else {var plurminutes = " minute "};