From 4eef3e5a09f6dcdddb654e05a77831ef27a3a537 Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Fri, 20 Mar 2020 14:33:46 +0100
Subject: [PATCH] AK: Add StringBuilder::join() for joining collections with a
 separator

This patch adds a generic StringBuilder::join(separator, collection):

    Vector<String> strings = { "well", "hello", "friends" };
    StringBuilder builder;
    builder.join("+ ", strings);
    builder.to_string(); // "well + hello + friends"
---
 AK/StringBuilder.h | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/AK/StringBuilder.h b/AK/StringBuilder.h
index 139fe3017a2..fc627b230bb 100644
--- a/AK/StringBuilder.h
+++ b/AK/StringBuilder.h
@@ -56,6 +56,19 @@ public:
     bool is_empty() const { return m_length == 0; }
     void trim(size_t count) { m_length -= count; }
 
+    template<class SeparatorType, class CollectionType>
+    void join(const SeparatorType& separator, const CollectionType& collection)
+    {
+        bool first = true;
+        for (auto& item : collection) {
+            if (first)
+                first = false;
+            else
+                append(separator);
+            append(item);
+        }
+    }
+
 private:
     void will_append(size_t);