From fd55be28fa73c507f9fee3956b1d06679318b00d Mon Sep 17 00:00:00 2001
From: Mike Helmick <mike.helmick@gmail.com>
Date: Mon, 2 Oct 2023 21:31:32 -0700
Subject: [PATCH] Map ptr (#5)

* add map conversion

* map to pointers

* lint
---
 slice/map.go      | 11 +++++++++++
 slice/map_test.go | 20 ++++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/slice/map.go b/slice/map.go
index 2ed4606..2f66759 100644
--- a/slice/map.go
+++ b/slice/map.go
@@ -29,3 +29,14 @@ func Map[T any, R any](in []T, fn MapFn[T, R]) []R {
 	}
 	return rtn
 }
+
+// MapToPtr transforms a slice into a slice of pointers
+// to the same elements.
+func MapToPtr[T any](in []T) []*T {
+	rtn := make([]*T, len(in))
+	for i, e := range in {
+		e := e
+		rtn[i] = &e
+	}
+	return rtn
+}
diff --git a/slice/map_test.go b/slice/map_test.go
index 7ed255b..37b7795 100644
--- a/slice/map_test.go
+++ b/slice/map_test.go
@@ -71,3 +71,23 @@ func TestMap(t *testing.T) {
 		t.Fatalf("mismatch (-want, +got):\n%s", diff)
 	}
 }
+
+func TestMapPtr(t *testing.T) {
+	t.Parallel()
+	in := []Person{
+		{
+			Name: "Alice",
+			Age:  30,
+		},
+		{
+			Name: "Bob",
+			Age:  31,
+		},
+	}
+
+	got := slice.MapToPtr(in)
+	want := []*Person{&in[0], &in[1]}
+	if diff := cmp.Diff(want, got); diff != "" {
+		t.Fatalf("mismatch (-want, +got):\n%s", diff)
+	}
+}