Mockup implementation of a DateTime Tagger. Requires underscore.js and doesn't yet follow the pictagger.api. Use with care

DateTime Tagger

function dateTagger(date) {
    var months = ['january', 'february', 'march', 'april', 'may', 'june', 'july', 'august', 'september', 'october', 'november', 'december'];
    var weekdays = ['sunday', 'monday', 'tuesday', 'wednesday', 'thursday', 'friday', 'saturday'];

    function getWeekOfYear(date) {
        a = new Date(date.getFullYear(), date.getMonth(), date.getDate() - date.getDay() + 5);
        b = new Date(a.getFullYear(), 0, 4);
        return ~~ ((a - b) / 864e5 / 7 + 1.5);
    }

    function getDaytime(date) {
        var hours = date.getHours();
        var daytimes = ['night', 'morning', 'noon', 'afternoon', 'evening', 'night'];
        var daytimeBegins = [6, 11, 13, 18, 21];
        return daytimes[_(daytimeBegins).sortedIndex(hours)];
    }

    function getSeason(date) {
        var dYear = date.getFullYear();
        var seasonStarts = [
        new Date(dYear, 2, 20), //SPRING
        new Date(dYear, 5, 21), //SUMMER
        new Date(dYear, 8, 22), //AUTUMN
        new Date(dYear, 11, 21) //WINTER
        ];
        var seasons = ['winter', 'spring', 'summer', 'autumn', 'winter'];
        return seasons[_(seasonStarts).sortedIndex(date)]
    }

    function zeropad(num) {
        return (num < 10 ? '0' + num : num)
    }

    return [{
        category: 'year',
        name: 'year' + date.getFullYear()
    }, {
        category: 'season',
        name: getSeason(date)
    }, {
        category: 'month',
        name: months[date.getMonth()]
    }, {
        category: 'daytime',
        name: getDaytime(date)
    }, {
        category: 'calweek',
        name: 'week' + zeropad(getWeekOfYear(date))
    }, {
        category: 'weekday',
        name: weekdays[date.getDay()]
    }, {
        category: 'monthday',
        name: 'day' + zeropad(date.getDate())
    }]
}