JSON fields are not returned as an object (when stored as a string)

At the moment i need to use for every JSON field this code before storing an item:

``` javascript
User.validate('settings', function(err) {
if (typeof this.settings !== 'object') {
try {
this.settings= JSON.parse(this.settings);
} catch (e) {
err();
}
}
}, {
message: 'Invalid JSON'
});
```

Would be nice if there would exist a function that does that automatically and throws an error when the field can't be converted to an object.