function isDate(value) {
      return value && typeof value == 'object' && toString.call(value) == dateClass || false;
    }
Checks if `value` is a date.

@static
@memberOf _
@category Objects
@param {*} value The value to check.
@returns {boolean} Returns `true` if the `value` is a date, else `false`.
@example

_.isDate(new Date);
// => true