javascript for array rotation

Question

Trying to understand how the code below always brings up a number between 0-6

var dayInMili = 86400000;
var weekInMili = 604800000;
//dateTime() returns miliseconds since Thurs, Jan 1 1970, need to account for week starting Monday not Thursday.
while (currentTime.getDay() != 1){
  currentTime.setTime(currentTime.getTime() - dayInMili);
}
//we need to find the number of weeks since the beginning of the year so we can
//  use that to determine schedule rotation
var weeks = Math.floor(currentTime.getTime() / weekInMili );
var startPoint = weeks % 7;

Brad · Accepted Answer · 2011-07-21 03:49:02Z

4

The modulo operator in the last line returns the remainder after dividing by seven. So in this case, the result assigned to startPoint is always going to be 0 - 6.

answered Jul 21, 2011 at 3:49

Brad

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Paul · Accepted Answer · 2011-07-21 03:48:18Z

4

startPoint = weeks % 7;

Is equivalent to taking weeks, dividing it by 7, and storing the remainder in startPoint. The remainder is always going to be between 0 and 6 for example:

answered Jul 21, 2011 at 3:48

Paul

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