About the settings of vue routing cache clearing

/* Page data cache */
var _CACHE_OBJS = {};
 
function _init_cache(comp, key, cache) {
 var obj = cache[key];
 if (obj !== undefined) {
 comp[key] = obj;
 }
 var deep = typeof comp[key] === 'object';
 comp.$watch(key,
 function (val) {
  //("page " + key + " updated");
  cache[key] = val;
 }, {
  deep: deep
 });
}
 
 
var _PAGE_CACHE = {
 /*
  * Initialize page cache data
  * comp: current page component object
  * path: Current page vue router path
  * data: The name of the data object that needs to be cached, or the name array
  */
 cache: function (comp, path, data) {
 if (data == '' || data == undefined || data == null) {
  data = restore(comp._data);
 }
 var cache = _CACHE_OBJS[path];
 if (cache === undefined) {
  cache = {};
  _CACHE_OBJS[path] = cache;
 }
 if (typeof data == 'string') {
  _init_cache(comp, data, cache);
 } else {
  var i;
  for (i = 0; i < ; ++i) {
  _init_cache(comp, data[i], cache);
  }
 }
 (_CACHE_OBJS, "Page Data Cache");
 },
 
 /* Clear page cache */
 clear: function (path) {
 delete _CACHE_OBJS[path];
 },
 
 /* Clear all cached data */
 reset: function () {
 //("reset page cache");
 _CACHE_OBJS = {};
 },
 /* Check whether the current page cache exists based on the path*/
 has_cache: function (path) {
 return _CACHE_OBJS[path] !== undefined && !isEmptyObject(_CACHE_OBJS[path]);
 }
};
 
.$cache = _PAGE_CACHE;
/* eslint-disable no-new */
 
var restore = function (vueObject) {
 var result = [];
 for (var index in vueObject) {
 (index);
 }
 return result;
};
 
var isEmptyObject = function (obj) {
 for (var key in obj) {
 return false;
 }
 return true;
}