From 722d61a8a282ab9f2097f9d0abaedebf5f4c5d41 Mon Sep 17 00:00:00 2001
From: Edoardo Ranghieri <edoardo@ranghieri.com>
Date: Mon, 20 Feb 2023 23:11:59 +0100
Subject: [PATCH] perf: faster string functions instead of regexes

---
 src/index.ts  | 19 ++++++++++++++-----
 tsconfig.json |  2 +-
 2 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/src/index.ts b/src/index.ts
index 38ec57d..462f187 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -25,7 +25,7 @@ export function UUIDtoULID(uuid: string, opts?: NullOnInvalidInput | ThrowOnInva
 		throw new Error("UUID to ULID conversion failed: invalid UUID input");
 	}
 
-	const ulid = crockfordEncode(Buffer.from(uuid.replace(/-/g, ""), "hex"));
+	const ulid = crockfordEncode(Buffer.from(uuid.replaceAll("-", ""), "hex"));
 
 	return ulid;
 }
@@ -46,10 +46,19 @@ export function ULIDtoUUID(ulid: string, opts?: NullOnInvalidInput | ThrowOnInva
 		throw new Error("ULID to UUID conversion failed: invalid ULID input");
 	}
 
-	const uuid = crockfordDecode(ulid)
-		.toString("hex")
-		.replace(/^(.{8})(.{4})(.{4})(.{4})(.{12})$/, "$1-$2-$3-$4-$5") // add hyphens
-		.toLowerCase();
+	let uuid = crockfordDecode(ulid).toString("hex");
+
+	// add hyphens
+	uuid =
+		uuid.substring(0, 8) +
+		"-" +
+		uuid.substring(8, 12) +
+		"-" +
+		uuid.substring(12, 16) +
+		"-" +
+		uuid.substring(16, 20) +
+		"-" +
+		uuid.substring(20);
 
 	return uuid;
 }
diff --git a/tsconfig.json b/tsconfig.json
index e10029d..ffa3bcf 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -2,7 +2,7 @@
 	"compilerOptions": {
 		"target": "ESNext",
 		"module": "CommonJS",
-		"lib": [],
+		"lib": ["ES2021.String"],
 		"skipLibCheck": true,
 		"sourceMap": true,
 		"outDir": "./dist",