Bug: The calendar displays the month's first date as Sunday, except in the years 2080 and 2081

[aj3sh]

I was exploring the demo site and came across this issue. Since the bug provides incorrect information to users, I reported it immediately. I haven't looked it in detail yet.

For years 2080 and 2081:

For other years:

[aj3sh]

Update:

It seems like the full monthly data are only available for 2080 and 2081.

/**
 * @description
 * This is the data for the months of the year.
 * The first element of the tuple is the number of days in each month.
 * Each month is an array of 3 elements. The first element is the number of days after which the month starts and the second element is the number of days in the month. The third element is the number of days after which next month starts.
 * The second element of the tuple is the total number of days in the year.
 * The data is from 2000 BS to 2099 BS.
 */
...
[
  [
    [0, 31, 0],
    [0, 31, 0],
    [0, 32, 0],
    [0, 31, 0],
    [0, 31, 0],
    [0, 31, 0],
    [0, 30, 0],
    [0, 29, 0],
    [0, 30, 0],
    [0, 29, 0],
    [0, 30, 0],
    [0, 30, 0],
  ],
  365,
], // 2079 BS
[
  [
    [5, 31, 6],
    [1, 32, 9],
    [5, 31, 6],
    [1, 32, 9],
    [5, 31, 6],
    [1, 30, 11],
    [3, 30, 9],
    [5, 30, 7],
    [0, 29, 13],
    [1, 29, 12],
    [2, 30, 10],
    [4, 30, 8],
  ],
  365,
], // 2080 BS
...