Set of Date-Helper-Functions

dateHelpers.js

/**
* Get the last full our of given date or now
*/
function getPrevFullHour(date) {
  if (!date) {
    date = new Date();
  }
  var copiedDate = new Date(date);

  copiedDate.setMinutes(0);
  copiedDate.setSeconds(0);
  return copiedDate;
}

/**
* Get the last our of given date or now
*/
function getPrevHour(date) {
  if (!date) {
    date = new Date();
  }

  var copiedDate = new Date(date);

  copiedDate.setHours(date.getHours() - 1);
  copiedDate.setSeconds(0);
  return copiedDate;
}

/**
* Get the date count of days ago
* optionally: set the day to 00:00:00
*/
function getDaysAgo(daysCount, date, midnight) {
  if (!daysCount) {
    daysCount = 7;
  }

  if (!date) {
    date = new Date();
  }

  var copiedDate = new Date(date);

  copiedDate.setDate(copiedDate.getDate() - daysCount);
  copiedDate.setSeconds(0);

  if (midnight === true) {
    copiedDate.setHours(0);
    copiedDate.setMinutes(0);
  }

  return copiedDate;
}

// Current
var date = new Date(); // 
console.log('Current Date', date); // Current Date Mon Aug 28 2017 10:36:23 GMT+0200 (CEST)
console.log('Previous full hour', getPrevFullHour(date)); // Previous full hour Mon Aug 28 2017 10:00:00 GMT+0200 (CEST)
console.log('Previous hour', getPrevHour(date)); // Previous hour Mon Aug 28 2017 09:36:00 GMT+0200 (CEST)
console.log('7 days ago', getDaysAgo(7, date)); // 7 days ago Mon Aug 21 2017 10:36:00 GMT+0200 (CEST)
console.log('7 days ago at midnight', getDaysAgo(7, date, true)); // 7 days ago at midnight Mon Aug 21 2017 00:00:00 GMT+0200 (CEST)