function cacheHas(cache, value) {
	  var map = cache.__data__;
	  if (isKeyable(value)) {
	    var data = map.__data__,
	        hash = typeof value == 'string' ? data.string : data.hash;

	    return hash[value] === HASH_UNDEFINED;
	  }
	  return map.has(value);
	}
Checks if `value` is in `cache`.

@private
@param {Object} cache The set cache to search.
@param {*} value The value to search for.
@returns {number} Returns `true` if `value` is found, else `false`.