From e3162f7a7e810b74ba417590657a53e00c3b2f76 Mon Sep 17 00:00:00 2001
From: Jacky Zhao <j.zhao2k19@gmail.com>
Date: Wed, 1 Jan 2025 12:11:16 -0800
Subject: [PATCH] chore: joinSegments fix + tests

---
 quartz/util/path.test.ts | 19 +++++++++++++++++++
 quartz/util/path.ts      | 25 ++++++++++++++++++-------
 2 files changed, 37 insertions(+), 7 deletions(-)

diff --git a/quartz/util/path.test.ts b/quartz/util/path.test.ts
index 7e9c4c84a32ac..687e6935937c8 100644
--- a/quartz/util/path.test.ts
+++ b/quartz/util/path.test.ts
@@ -158,6 +158,25 @@ describe("transforms", () => {
       path.isRelativeURL,
     )
   })
+
+  test("joinSegments", () => {
+    assert.strictEqual(path.joinSegments("a", "b"), "a/b")
+    assert.strictEqual(path.joinSegments("a/", "b"), "a/b")
+    assert.strictEqual(path.joinSegments("a", "b/"), "a/b/")
+    assert.strictEqual(path.joinSegments("a/", "b/"), "a/b/")
+
+    // preserve leading and trailing slashes
+    assert.strictEqual(path.joinSegments("/a", "b"), "/a/b")
+    assert.strictEqual(path.joinSegments("/a/", "b"), "/a/b")
+    assert.strictEqual(path.joinSegments("/a", "b/"), "/a/b/")
+    assert.strictEqual(path.joinSegments("/a/", "b/"), "/a/b/")
+
+    // works with protocol specifiers
+    assert.strictEqual(path.joinSegments("https://example.com", "a"), "https://example.com/a")
+    assert.strictEqual(path.joinSegments("https://example.com/", "a"), "https://example.com/a")
+    assert.strictEqual(path.joinSegments("https://example.com", "a/"), "https://example.com/a/")
+    assert.strictEqual(path.joinSegments("https://example.com/", "a/"), "https://example.com/a/")
+  })
 })
 
 describe("link strategies", () => {
diff --git a/quartz/util/path.ts b/quartz/util/path.ts
index d2409e1cdf54d..580707f2c8a6d 100644
--- a/quartz/util/path.ts
+++ b/quartz/util/path.ts
@@ -183,15 +183,26 @@ export function slugTag(tag: string) {
 }
 
 export function joinSegments(...args: string[]): string {
-  return args
+  if (args.length === 0) {
+    return ""
+  }
+
+  let joined = args
     .filter((segment) => segment !== "")
-    .map((segment, index) =>
-      index === 0
-        ? // Deduplicate but not remove leading slashes for first segment
-          segment.replace(/\/+$/g, "").replace(/^\/\/+/g, "/")
-        : segment.replace(/^\/+|\/+$/g, ""),
-    )
+    .map((segment) => stripSlashes(segment))
     .join("/")
+
+  // if the first segment starts with a slash, add it back
+  if (args[0].startsWith("/")) {
+    joined = "/" + joined
+  }
+
+  // if the last segment is a folder, add a trailing slash
+  if (args[args.length - 1].endsWith("/")) {
+    joined = joined + "/"
+  }
+
+  return joined
 }
 
 export function getAllSegmentPrefixes(tags: string): string[] {