Some javascript classes to create a list of categories from a range of dates by year, month or day.

date-categorizers.js

DateCategorizer = class DateCategorizer {
    constructor(category_period, initial_date, final_date) {
        this.period = category_period;
        this.initial = initial_date;
        this.final = final_date;
        this.categorizer = this.categorizer_factory();
        this.categories = [];
        this.update_categories();
    }

    categorizer_factory() {
        if (this.period === 'day') {
            return new DayCategorizer(this.initial, this.final)
        } else if (this.period === 'month') {
            return new MonthCategorizer(this.initial, this.final)
        } else {  // period === 'year'
            return new YearCategorizer(this.initial, this.final)
        }
    }

    update_categories() {
        this.categories = this.categorizer.get_categories();
    }
}


AbstractCategorizer = class AbstractCategorizer {
    constructor(initial, final) {
        this.initial = new Date(initial);
        this.final = new Date(final);
        this._categories = [];
        this.update_categories();
    }

    // abstract method
    update_categories() {
        this._categories = [];
    }

    get_categories() {
        return this._categories
    }

    clone(date) {
        var tt = date.toString();
        var copy = new Date(tt);
        return copy
    }

    format(date) {
        return date.toISOString().substring(0, 10);
    }
}


DayCategorizer = class DayCategorizer extends AbstractCategorizer {
    update_categories() {
        var date = this.clone(this.initial);
        var category = this.format(date);
        var final = this.format(this.final);
        while (category <= final) {
            this._categories.push(category);
            date.setDate(date.getDate() + 1);
            var category = this.format(date);
        }
    }
}


MonthCategorizer = class DayCategorizer extends AbstractCategorizer {
    update_categories() {
        var date = this.clone(this.initial);
        var category = this.format(date);
        var final = this.format(this.final);
        while (category <= final) {
            this._categories.push(category);
            date.setMonth(date.getMonth() + 1);
            var category = this.format(date);
        }
    }

    format(date) {
        var date = super.format(date);
        return date.substring(0,7)
    }
}


YearCategorizer = class DayCategorizer extends AbstractCategorizer {
    update_categories() {
        var date = this.clone(this.initial);
        var category = this.format(date);
        var final = this.format(this.final);
        while (category <= final) {
            this._categories.push(category);
            date.setFullYear(date.getFullYear() + 1);
            var category = this.format(date);
        }
    }

    format(date) {
        var date = super.format(date);
        return date.substring(0,4)
    }
}