---
title: Closure expressions should not be nested too deeply
description: Datadog, the leading service for cloud-scale monitoring.
breadcrumbs: >-
  Docs > Datadog Security > Code Security > Static Code Analysis (SAST) > SAST
  Rules > Closure expressions should not be nested too deeply
---

# Closure expressions should not be nested too deeply

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## Metadata{% #metadata %}

**ID:** `swift-code-style/nested-closure`

**Language:** Swift

**Severity:** Notice

**Category:** Code Style

## Description{% #description %}

Closure expressions should not be nested too deeply, as excessive nesting makes code harder to read, understand, and maintain. Closures are intended to provide clear, concise logic, but when stacked inside one another, they quickly become confusing and error-prone. Extracting nested logic into separate functions keeps the codebase cleaner and easier to follow.

## Non-Compliant Code Examples{% #non-compliant-code-examples %}

```swift
import SwiftUI

struct AlbumDetail: View {
	var album: Album

	var body: some View {
		List(album.songs) { song in 
			HStack {
				Image(album.cover)
				VStack(alignment: .leading) {
					Text(song.title)
					Text(song.artist.name)
						.foregroundStyle(.secondary)

          VStack(alignment: .leading) {
            Text(song.title)
            Text(song.artist.name)
              .foregroundStyle(.secondary)
            VStack(alignment: .leading) {
              Text(song.title)
              Text(song.artist.name)
                .foregroundStyle(.secondary)
            }
          }
				}
			}
		}
	}
}
```

## Compliant Code Examples{% #compliant-code-examples %}

```swift
import SwiftUI

struct AlbumDetail: View {
	var album: Album

	var body: some View {
		List(album.songs) { song in 
			HStack {
				Image(album.cover)
				VStack(alignment: .leading) {
					Text(song.title)
					Text(song.artist.name)
						.foregroundStyle(.secondary)
				}
			}
		}
	}
}
```

```swift
func multPlus(x:Int) {
  foobar(x) {
    print(x * 42)
  }
  print(x + 42)
}

foo(42) { (x: Int) in
    bar(x, multPlus)
    print(x - 42)
}
```
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