# setExtra(key, extra)

{% hint style="info" %}
As existing extra is being entirely overwritten, be careful how / when you use it. Simply, use this method with caution.
{% endhint %}

### **Arguments**

1. `key` *(string)*: Key to store the extra under (represents given item).
2. `extra` *(object)*: Extra data to replace existing one.

### **Throws**

1. If `extra` is not an object, it will throw `'extra' must be an object.`

### **Lifecycle**

1. **preSetExtra**

   **Event name:** `preSetExtra`\
   **Properties passed:**

   * `cacheInstance` reference to cache instance (`this`)
   * `key` key passed to `setExtra` method
   * `extra` extra passed to `setExtra` method

   **Returns:** *(object)*: object containing properties:

   * `cacheInstance` reference to cache instance (`this`)
   * `key` key passed through handlers added for `preSetExtra` event
   * `extra` extra passed through handlers added for `preSetExtra` event<br>
2. **postSetExtra**

   **Event name:** `postSetExtra`\
   **Properties passed:**

   * `cacheInstance` reference to cache instance (`this`) returned by `preSetExtra`
   * `key` key returned by `preSetExtra`
   * `extra` extra (object) returned by adapter using its [setExtra](https://stash-it.gitbook.io/stash-it/api/adapter/setextra-key-extra) method

   **Returns:** *(object)*: object containing properties:

   * `cacheInstance` reference to cache instance (`this`)
   * `key` key passed through handlers added for `postSetExtra` event
   * `extra` extra passed through handlers added for `postSetExtra` event<br>

   Eventually `setExtra` returns extra returned by `postSetExtra`.

### **Example**

```javascript
// Existing extra
{ 
    some: 'data'
}

cache.setExtra(key, { foo: 'bar' });

// Extra after setting new one
{
    foo: 'bar'
}
```