---
title: "fetchInstalledExtensions(completionHandler:)"
framework: FSKit
role: symbol
role_heading: Instance Method
platforms: [macOS 15.4+]
path: "fskit/fsclient/fetchinstalledextensions(completionhandler:)"
---

# fetchInstalledExtensions(completionHandler:)

Asynchronously retrieves an list of installed file system modules.

## Declaration

```swift
func fetchInstalledExtensions(completionHandler: @escaping @Sendable ([FSModuleIdentity]?, (any Error)?) -> Void)
```

```swift
var installedExtensions: [FSModuleIdentity] { get async throws }
```

## Parameters

- `completionHandler`: A block or closure that executes when FSKit finishes its fetch process. If the fetch succeeds, the first parameter contains an array of doc://FSKit/documentation/FSKit/FSModuleIdentity instances that identify installed modules. If the fetch fails, the second parameter contains an error detailing the failure.

## Discussion

Discussion In Swift, you can either call this method and pass a completion handler closure, or get the value of the installedExtensions property with the async keyword.

## See Also

### Discovering installed extensions

- [FSModuleIdentity](fskit/fsmoduleidentity.md)