Study Streak

studystreak.js

// Values for dates are received from the server
// This is sorted in most recent date first to least to recent last.
dates = [];

// Go through each date
for (i=0; i <= dates.length-1; i++) {

  var date = date[i]; // Get the UTC date
  var localDate = moment.utc(date).local().format('DDMMYY'); // Covert it to a local date

  // If the date is the first in the list i.e. the last test recordeed
  if (i === 0) {
    var today = moment().format('DDMMYY');
    var yesterday = moment().format('DDMMYY');
    
    // Check if it was logged today or yesterday
    if (localDate === today) ||
        localDate === yesterday) {
        streak += 1;
    }
  }
  else { // If not the first date in the list
    // Get the previous date in the list
    var previousDate = moment.utc(dates[i-1]).local().format('DDMMYY');
    var previousDateYesterday = moment.utc(dates[i-1]).local().subtract(1, 'days').format('DDMMYY');
    
    // Make sure that the dates are not the same, we don't want to add to the streak if the dates are from the same day
    // as the streak is counted daily.
    if (localDate !== previousDate) {
      // If the date is the same as the date before it subtracted by one day then add to streak
      if (localDate === previousDateYesterday) {
        streak += 1;
      }
      else {
        // If not then the streak is no longer valid.
        break;
      }
    }
  }
}