Swift Lazy Variables that Load more than Once (Computed Properties?)

Question

I'm trying to translate some Objective-C code that was essentially lazy loading a variable multiple times. The code was similar to the following: ``` -(NSFetchedResultsController *)fetchedResultsController { if (_fetchedResultsController != nil) { return _fetchedResultsController; } //...code to build the fetchedResultsController with a new predicate ``` Whenever they wanted to rebuild the fetchedResultsController to use a new predicate, they would just set it to "nil" and call it, and it would rebuild it with a new predicate. I'm struggling to do this same task in Swift. As far as I can tell, Swift lazy variables become normal variables after they are called for the first time. This is causing issues for me because if I try to set my swift variable back to nil, and recall it, it doesn't rebuild but remains nil. The working code to load my fetchedResultsController as a lazy varaible is below. I've tried changing it to a computed property by adding a check if its nil and have it within…

Accepted Answer

You can create something similar to the Objective-C method using a computed property backed by an optional variable.

```
var _fetchedResultsController: NSFetchedResultsController?

var fetchedResultsController: NSFetchedResultsController {
    get {
        if _fetchedResultsController != nil {
            return _fetchedResultsController!
        }
        //create the fetched results controller...
        return _fetchedResultsController!
    }
}
```

Swift Lazy Variables that Load more than Once (Computed Properties?)

Solution

Problem