From b98a061d965e8edb06769570fc61b7c45023f18c Mon Sep 17 00:00:00 2001
From: Kuba Orlik <kontakt@kuba-orlik.name>
Date: Sun, 21 Nov 2021 18:19:58 +0100
Subject: [PATCH] Make render throttled so they don't block the thread

---
 memory.ts | 17 ++++++++++++++++-
 util.ts   | 18 ++++++++++++++++++
 2 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/memory.ts b/memory.ts
index f9bec5a..95cbfb6 100644
--- a/memory.ts
+++ b/memory.ts
@@ -1,10 +1,11 @@
 import ExtendedRequest from "./extended-request";
-import { getshorthost } from "./util";
+import { getshorthost, makeThrottle } from "./util";
 import { EventEmitter } from "events";
 import { RequestCluster } from "./request-cluster";
 
 export default class Memory extends EventEmitter {
   origin_to_history = {} as Record<string, Record<string, RequestCluster>>;
+  private throttle = makeThrottle(200);
   async register(request: ExtendedRequest) {
     await request.init();
     console.log("registering request for", request.origin);
@@ -34,6 +35,20 @@ export default class Memory extends EventEmitter {
     );
   }
 
+  emit(eventName: string, immediate = false) {
+    try {
+      if (immediate) {
+        super.emit(eventName);
+        return;
+      } else {
+        this.throttle(() => super.emit(eventName));
+      }
+      return true;
+    } catch (e) {
+      debugger;
+    }
+  }
+
   getClustersForOrigin(origin: string): Record<string, RequestCluster> {
     return this.origin_to_history[origin] || {};
   }
diff --git a/util.ts b/util.ts
index 24f80ee..2b5340c 100644
--- a/util.ts
+++ b/util.ts
@@ -138,3 +138,21 @@ export function toBase64(file: File): Promise<string> {
     FR.readAsDataURL(file);
   });
 }
+
+export function makeThrottle(interval: number) {
+  let last_emit = 0;
+  function emit(callback: () => void) {
+    if (Date.now() - last_emit > interval) {
+      callback();
+      last_emit = Date.now();
+      return true;
+    } else {
+      return false;
+    }
+  }
+  return function (callback: () => void) {
+    if (!emit(callback)) {
+      setTimeout(() => emit(callback), interval);
+    }
+  };
+}