convert time ago time to local time using offset

README.md

takes '3 hours 10 minutes ago' and convert to actual time

convert_time_ago.js

var timeStr = '3 hours 10 minutes ago';

function splitTimeAgoString(timeString) {
  var timeArray = timeStr.split(' ');

  var timeDelta = timeArray.pop();
  
  if (timeArray.length % 2 !== 0) {
    throw new Error('Time array unexpected: ' + JSON.stringify(timeArray));
  }

  var timeValues = timeArray.reduce( function(result, value, index, array) {
    if (index % 2 === 0)
      result.push({
        value: array[index],
        unit: array[index + 1],
      });
    return result;
  }, []);
  
  return { 
    timeValues: timeValues,
    timeDelta: timeDelta,
  };
}

function convertTimeAgoToSec(timeUnits) {
  var timeValues = timeUnits.timeValues;
  var timeDelta = timeUnits.timeDelta;
  var seconds = timeValues.reduce( function(result, time) {
    switch(time.unit) {
      case 'days':
        result += (time.value * 60 * 60 * 24);
        break;
      case 'hours':
        result += (time.value * 60 * 60);
        break;
      case 'minutes':
        result += (time.value * 60);
        break;
      case 'seconds':
        result += time.value;
        break;
      default:
        console.error('unknown time unit: ' + JSON.stringify(time, null, 2));
        result += 0;
    }
    return result;
  }, 0);
  
  return timeDelta === 'ago' ? -seconds : seconds;
}

function getCheckedTime(timeStr) {
  try {
    var timeUnits = splitTimeAgoString(timeStr);
    var timeDiff = convertTimeAgoToSec(timeUnits);
    var checkedDate = new Date(Date.now() + timeDiff * 1000);
    
    return checkedDate.toString();
  } catch(e) {
    console.error('ERROR: getCheckedTime' + e);
    return timeStr;
  } 
}


console.log(getCheckedTime(timeStr));