From af22ea6ec9e8bb40b5e3a3a18be1bb9422af0c21 Mon Sep 17 00:00:00 2001
From: Hayleigh Thompson <me@hayleigh.dev>
Date: Sat, 25 Jul 2026 23:31:51 +0200
Subject: [PATCH] =?UTF-8?q?=E2=9C=A8=20Add=20a=20'domain'=20function=20for?=
 =?UTF-8?q?=20converting=20nsid=20authorities=20to=20normal=20domain=20nam?=
 =?UTF-8?q?es.?=
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---
 src/at/nsid.gleam | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/src/at/nsid.gleam b/src/at/nsid.gleam
index 8796076..dc4e4f9 100644
--- a/src/at/nsid.gleam
+++ b/src/at/nsid.gleam
@@ -340,6 +340,17 @@ pub fn name(nsid: Nsid) -> String {
   nsid.name
 }
 
+/// Construct a domain name from an [`Nsid`](#Nsid) authority. This reverses the
+/// authority segments back into the order they would appear in a typical domain
+/// name, such as `"bsky.app"` or `"atproto.com"`.
+/// 
+pub fn domain(nsid: Nsid) -> String {
+  let assert [tld, ..rest] = nsid.authority
+  use out, segment <- list.fold(rest, tld)
+
+  segment <> "." <> out
+}
+
 // CONVERSIONS -----------------------------------------------------------------
 
 /// Convert an [`Nsid`](#Nsid) back into its string representation.
-- 
2.51.2