qcobjects-docs/public/templates/components/markdown/en/page_en_20_1_2.md

The official app and website for documentation of QCObjects

### ComplexStorageCache

With **ComplexStorageCache** you can handle a cache for any object and save it in the local storage.

#### Usage:
```javascript
var cache = new ComplexStorageCache({
                      index:object.id, // Object Index
                      load:(cacheController)=>{}, // A function to execute for the first time
                      alternate: (cacheController)=>{} // The alternate function to execute from the second time the source coude is loaded
                      });
```

#### Example:
```javascript
var dataObject = {id:1,
                  prop1:1,
                  prop2:2
                };

var cache = new ComplexStorageCache({
    index: dataObject.id,
    load: (cacheController) => {
      dataObject = {
              id:dataObject.id,
              prop1:dataObject.prop1*2, // changing a property value
              prop2:dataObject.prop2
            };
      return dataObject;
    },
    alternate: (cacheController) => {
      dataObject = cacheController.cache.getCached(dataObject.id); // setting dataObject with the cached value
      return;
    }
  });

// Next time you can get the object from the cache
var dataObjectCopyFromCache = cache.getCached(dataObject.id);
console.log(dataObjectCopyFromCache); // will show the very same object value than dataObject
```