From 8aa089178a54559cbc4e4fe84a618fc7535f178c Mon Sep 17 00:00:00 2001
From: syuilo <Syuilotan@yahoo.co.jp>
Date: Thu, 18 Mar 2021 10:49:14 +0900
Subject: Improve server performance

---
 src/misc/cache.ts | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)
 create mode 100644 src/misc/cache.ts

(limited to 'src/misc')

diff --git a/src/misc/cache.ts b/src/misc/cache.ts
new file mode 100644
index 0000000000..356a3de7b9
--- /dev/null
+++ b/src/misc/cache.ts
@@ -0,0 +1,25 @@
+export class Cache<T> {
+	private cache: Map<string | null, { date: number; value: T; }>;
+	private lifetime: number;
+
+	constructor(lifetime: Cache<never>['lifetime']) {
+		this.lifetime = lifetime;
+	}
+
+	public set(key: string | null, value: T):void {
+		this.cache.set(key, {
+			date: Date.now(),
+			value
+		});
+	}
+
+	public get(key: string | null): T | null {
+		const cached = this.cache.get(key);
+		if (cached == null) return null;
+		if ((Date.now() - cached.date) > this.lifetime) {
+			this.cache.delete(key);
+			return null;
+		}
+		return cached.value;
+	}
+}
-- 
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