From 0cac22a7e0e3cc41eae8196869db45e48135835e Mon Sep 17 00:00:00 2001
From: Olivers Vitins <o.vitins@resultium.io>
Date: Sat, 4 May 2024 23:01:10 +0300
Subject: [PATCH] perf(changelog): improve generation time by ~2800 times (#23)

---
 src/commands/changelog.ts | 67 +++++++++++----------------------------
 1 file changed, 19 insertions(+), 48 deletions(-)

diff --git a/src/commands/changelog.ts b/src/commands/changelog.ts
index c9c8669..e769436 100644
--- a/src/commands/changelog.ts
+++ b/src/commands/changelog.ts
@@ -51,63 +51,34 @@ const command = new Command("changelog")
 
     for (const commit of commits) {
       const tag =
-        sort((await simpleGit().tags([`--contains=${commit.hash}`])).all)[0]! ||
-        unreleased;
+        (commit.refs.match(/tag: (\S+)(?:,|$)/)?.[1] ?? lastTag) || unreleased;
 
-      const currentCommitStack = parsedCommitStacks.find(
+      let currentCommitStackIndex = parsedCommitStacks.findIndex(
         (commitStack) => commitStack.version === tag,
-      ) || {
-        version: tag || unreleased,
-        breaking: [],
-        features: [],
-        fixes: [],
-        miscellaneous: [],
-      };
+      );
 
-      if (lastTag !== tag) {
-        parsedCommitStacks = [currentCommitStack, ...parsedCommitStacks];
+      if (currentCommitStackIndex === -1) {
+        parsedCommitStacks.push({
+          version: tag || unreleased,
+          breaking: [],
+          features: [],
+          fixes: [],
+          miscellaneous: [],
+        });
+
+        currentCommitStackIndex = parsedCommitStacks.findIndex(
+          (commitStack) => commitStack.version === tag,
+        );
       }
 
       if (commit.message.includes("!:")) {
-        parsedCommitStacks = [
-          {
-            ...currentCommitStack,
-            breaking: [...currentCommitStack.breaking, commit],
-          },
-          ...parsedCommitStacks.filter(
-            (commitStack) => commitStack.version !== tag,
-          ),
-        ];
+        parsedCommitStacks[currentCommitStackIndex].breaking.push(commit);
       } else if (commit.message.startsWith("feat")) {
-        parsedCommitStacks = [
-          {
-            ...currentCommitStack,
-            features: [...currentCommitStack.features, commit],
-          },
-          ...parsedCommitStacks.filter(
-            (commitStack) => commitStack.version !== tag,
-          ),
-        ];
+        parsedCommitStacks[currentCommitStackIndex].features.push(commit);
       } else if (commit.message.startsWith("fix")) {
-        parsedCommitStacks = [
-          {
-            ...currentCommitStack,
-            fixes: [...currentCommitStack.fixes, commit],
-          },
-          ...parsedCommitStacks.filter(
-            (commitStack) => commitStack.version !== tag,
-          ),
-        ];
+        parsedCommitStacks[currentCommitStackIndex].fixes.push(commit);
       } else {
-        parsedCommitStacks = [
-          {
-            ...currentCommitStack,
-            miscellaneous: [...currentCommitStack.miscellaneous, commit],
-          },
-          ...parsedCommitStacks.filter(
-            (commitStack) => commitStack.version !== tag,
-          ),
-        ];
+        parsedCommitStacks[currentCommitStackIndex].miscellaneous.push(commit);
       }
 
       lastTag = tag;