Function ceil

code/gmane/d3.v3.js:2408–2411

(date)

      return date - d0 < d1 - date ? d0 : d1;
    }
    function ceil(date) {
      step(date = local(new d3_date(date - 1)), 1);
      return date;
    }
    function offset(date, k) {
      step(date = new d3_date(+date), k);
      return date;