function _slicedToArray(arr, i) { return _arrayWithHoles(arr) || _iterableToArrayLimit(arr, i) || _unsupportedIterableToArray(arr, i) || _nonIterableRest(); }

function _nonIterableRest() { throw new TypeError("Invalid attempt to destructure non-iterable instance.\nIn order to be iterable, non-array objects must have a [Symbol.iterator]() method."); }

function _iterableToArrayLimit(arr, i) { if (typeof Symbol === "undefined" || !(Symbol.iterator in Object(arr))) return; var _arr = []; var _n = true; var _d = false; var _e = undefined; try { for (var _i = arr[Symbol.iterator](), _s; !(_n = (_s = _i.next()).done); _n = true) { _arr.push(_s.value); if (i && _arr.length === i) break; } } catch (err) { _d = true; _e = err; } finally { try { if (!_n && _i["return"] != null) _i["return"](); } finally { if (_d) throw _e; } } return _arr; }

function _arrayWithHoles(arr) { if (Array.isArray(arr)) return arr; }

function _createForOfIteratorHelper(o, allowArrayLike) { var it; if (typeof Symbol === "undefined" || o[Symbol.iterator] == null) { if (Array.isArray(o) || (it = _unsupportedIterableToArray(o)) || allowArrayLike && o && typeof o.length === "number") { if (it) o = it; var i = 0; var F = function F() {}; return { s: F, n: function n() { if (i >= o.length) return { done: true }; return { done: false, value: o[i++] }; }, e: function e(_e2) { throw _e2; }, f: F }; } throw new TypeError("Invalid attempt to iterate non-iterable instance.\nIn order to be iterable, non-array objects must have a [Symbol.iterator]() method."); } var normalCompletion = true, didErr = false, err; return { s: function s() { it = o[Symbol.iterator](); }, n: function n() { var step = it.next(); normalCompletion = step.done; return step; }, e: function e(_e3) { didErr = true; err = _e3; }, f: function f() { try { if (!normalCompletion && it["return"] != null) it["return"](); } finally { if (didErr) throw err; } } }; }

function _unsupportedIterableToArray(o, minLen) { if (!o) return; if (typeof o === "string") return _arrayLikeToArray(o, minLen); var n = Object.prototype.toString.call(o).slice(8, -1); if (n === "Object" && o.constructor) n = o.constructor.name; if (n === "Map" || n === "Set") return Array.from(o); if (n === "Arguments" || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)) return _arrayLikeToArray(o, minLen); }

function _arrayLikeToArray(arr, len) { if (len == null || len > arr.length) len = arr.length; for (var i = 0, arr2 = new Array(len); i < len; i++) { arr2[i] = arr[i]; } return arr2; }

import merge from './util/merge';
var default_date_options = {
  format: 'YYYY/MM/DD',
  delimiters: ['/', '-'],
  strictMode: false
};

function isValidFormat(format) {
  return /(^(y{4}|y{2})[\/-](m{1,2})[\/-](d{1,2})$)|(^(m{1,2})[\/-](d{1,2})[\/-]((y{4}|y{2})$))|(^(d{1,2})[\/-](m{1,2})[\/-]((y{4}|y{2})$))/gi.test(format);
}

function zip(date, format) {
  var zippedArr = [],
      len = Math.min(date.length, format.length);

  for (var i = 0; i < len; i++) {
    zippedArr.push([date[i], format[i]]);
  }

  return zippedArr;
}

export default function isDate(input, options) {
  if (typeof options === 'string') {
    // Allow backward compatbility for old format isDate(input [, format])
    options = merge({
      format: options
    }, default_date_options);
  } else {
    options = merge(options, default_date_options);
  }

  if (typeof input === 'string' && isValidFormat(options.format)) {
    var formatDelimiter = options.delimiters.find(function (delimiter) {
      return options.format.indexOf(delimiter) !== -1;
    });
    var dateDelimiter = options.strictMode ? formatDelimiter : options.delimiters.find(function (delimiter) {
      return input.indexOf(delimiter) !== -1;
    });
    var dateAndFormat = zip(input.split(dateDelimiter), options.format.toLowerCase().split(formatDelimiter));
    var dateObj = {};

    var _iterator = _createForOfIteratorHelper(dateAndFormat),
        _step;

    try {
      for (_iterator.s(); !(_step = _iterator.n()).done;) {
        var _step$value = _slicedToArray(_step.value, 2),
            dateWord = _step$value[0],
            formatWord = _step$value[1];

        if (dateWord.length !== formatWord.length) {
          return false;
        }

        dateObj[formatWord.charAt(0)] = dateWord;
      }
    } catch (err) {
      _iterator.e(err);
    } finally {
      _iterator.f();
    }

    return new Date("".concat(dateObj.m, "/").concat(dateObj.d, "/").concat(dateObj.y)).getDate() === +dateObj.d;
  }

  if (!options.strictMode) {
    return Object.prototype.toString.call(input) === '[object Date]' && isFinite(input);
  }

  return false;
}