timer({
  container: '.timer',
  date: '09/30/2018',
  template: function() {
    return `
      <div>
        <span v-time-days></span>
        :
        <span v-time-hours></span>
        :
        <span v-time-minutes></span>
        :
        <span v-time-seconds></span>
      </div>
    `;
  },
  finish: function() {
    return '<span>Время вышло</span>';
  }
});

function timer(options) {
  var setting = extend({
    container: '.timer',
    date: '09/30/2018',
    template: function() {},
    finish: function() {}
  }, options || {});

  var general = {
    context: document.querySelector(setting.container),
    date: new Date(setting.date).getTime(),
    time: {},
    inverval: 0
  };

  general.context.innerHTML = setting.template.call(general.context);

  initTimer();

  general.interval = setInterval(initTimer, 1e3);

  function initTimer() {
    var remaining = general.date - Date.now();
    general.time = getTimeObject(remaining);
    if (remaining <= 1e3) {
      var html = setting.finish.call(general.context);
      if (html) general.context.innerHTML = html;
      clearInterval(general.inverval);
    } else {
      changeTime(general.time);
    }
  }

  function changeTime(time) {
    ['days', 'hours', 'minutes', 'seconds'].forEach(function(name) {
      [].forEach.call(general.context.querySelectorAll('[v-time-' + name + ']'), function(node) {
        if (node.innerText !== time[name]) node.innerText = time[name];
      });
    });
  }

  function getTimeObject(time) {
    return doubleDigits({
      seconds: Math.floor((time / 1e3) % 60),
      minutes: Math.floor((time / 1e3 / 60) % 60),
      hours: Math.floor((time / (1e3 * 60 * 60) % 24)),
      days: Math.floor(time / (1e3 * 60 * 60 * 24))
    });
  }

  function doubleDigits(time) {
    if (typeof time === 'object') {
      for (var item in time) {
        time[item] = time[item] < 10 ? '0' + time[item] : String(time[item]);
      }
    } else {
      time = time < 10 ? '0' + time : time;
    }
    return time;
  }

  function extend(out) {
    out = out || {};
    for (var i = 1; i < arguments.length; i++) {
      var obj = arguments[i];
      if (!obj) continue;
      for (var key in obj) {
        if (obj.hasOwnProperty(key)) {
          if (typeof obj[key] === 'object') {
            out[key] = extend(out[key], obj[key]);
          }
          else {
            out[key] = obj[key];
          }
        }
      }
    }
    return out;
  }
}