Faster sort function (#195)

rjchatfield · stephencelis · commit 74f521128ca7 · 2019-03-23T11:18:20.000-04:00
Found a small change of building an array of snaps, *then* sorting them, it reduced on of our test cases from 6m 8s to just 9s. And noticed it crept over 2GB of memory usage.
diff --git a/Sources/SnapshotTesting/Snapshotting/Any.swift b/Sources/SnapshotTesting/Snapshotting/Any.swift
@@ -55,7 +55,12 @@ private func snap<T>(_ value: T, name: String? = nil, indent: Int = 0) -> String
 }
 
 private func sort(_ children: Mirror.Children) -> Mirror.Children {
-  return .init(children.sorted { snap($0) < snap($1) })
+  return .init(
+    children
+      .map({ (child: $0, snap: snap($0)) })
+      .sorted(by: { $0.snap < $1.snap })
+      .map({ $0.child })
+  )
 }
 
 /// A type with a customized snapshot dump representation.

Original file line number	Diff line number	Diff line change
`@@ -55,7 +55,12 @@ private func snap<T>(_ value: T, name: String? = nil, indent: Int = 0) -> String`
`55`	`55`	`}`
`56`	`56`
`57`	`57`	`private func sort(_ children: Mirror.Children) -> Mirror.Children {`
`58`		`- return .init(children.sorted { snap($0) < snap($1) })`
	`58`	`+ return .init(`
	`59`	`+ children`
	`60`	`+ .map({ (child: $0, snap: snap($0)) })`
	`61`	`+ .sorted(by: { $0.snap < $1.snap })`
	`62`	`+ .map({ $0.child })`
	`63`	`+ )`
`59`	`64`	`}`
`60`	`65`
`61`	`66`	`/// A type with a customized snapshot dump representation.`