Minutes per hour within date range in javascript

Question

How do build an array with minute counts per hour within a set date range.

Assuming you have these dates

const start = new Date('2019-04-04 12:14');
const end = new Date('2019-04-04 16:21');

How do you turn that into and array looking like this:

const minutes_per_hour = [
    {
        hour: 12,
        minute_count: 46
    },
    {
        hour: 13,
        minute_count: 60
    },
    {
        hour: 14,
        minute_count: 60
    },
    {
        hour: 15,
        minute_count: 60
    },
    {
        hour: 16,
        minute_count: 21
    }
];

Have you tried anything to solve the issue yourself? Also, it's not clear why "12:14" has a `minute_count` of 46 rather than 14... — Heretic Monkey, Apr 05 '19 at 13:16
@HereticMonkey It's a start date and time, so if you start at :14, theres 46 minutes left to fill the remaining timegap (until 13:00 in this case). — Caramiriel, Apr 05 '19 at 13:16
@Caramiriel that's a good clarification that should be incorporated in the question, no? — Heretic Monkey, Apr 05 '19 at 13:18
[This answer to a similar question should get you started](https://stackoverflow.com/a/4413687/215552). — Heretic Monkey, Apr 05 '19 at 13:22

Birjolaxew · Accepted Answer · 2019-04-05T13:56:43.370

Here's a simple function that should do what you want. It works by repeatedly calculating the minutes until the next hour (or end, if that's closer) and incrementing to the next hour, eventually stopping when end is reached.

/**
 * Gets the minutes in each sequential hour in a time range
 * @param {Date} start
 * @param {Date} end
 * @return {{hour:number, minute_count:number}[]}
 */
function getMinutesPerHour(start, end) {
  const outp = [];
  let current = start;
  while (current < end) {
    const minutesToNextHour = 60 - current.getMinutes();
    const nextHour = new Date(+current + minutesToNextHour * 60 * 1000);
    const minutes = nextHour > end
      ? end.getMinutes() - current.getMinutes()
      : minutesToNextHour;
    outp.push({ hour: current.getHours(), minutes: minutes, });
    current = nextHour;
  }
  return outp;
}

console.log(getMinutesPerHour(new Date('2019-04-04 12:14'), new Date('2019-04-04 16:21')));

Minutes per hour within date range in javascript

1 Answers1