Optimize subs and many other things

src/feed/Subscription.js

@@ -0,0 +1,51 @@
+import { useEffect, useMemo, useState } from "react";
+import { System } from "..";
+import { Subscriptions } from "../nostr/Subscriptions";
+
+/**
+ * 
+ * @param {Subscriptions} sub 
+ * @param {any} opt 
+ * @returns 
+ */
+export default function useSubscription(sub, opt) {
+    const [notes, setNotes] = useState([]);
+
+    const options = {
+        leaveOpen: false,
+        ...opt
+    };
+
+    useEffect(() => {
+        if (sub) {
+            sub.OnEvent = (e) => {
+                setNotes(n => {
+                    if (Array.isArray(n) && !n.some(a => a.id === e.id)) {
+                        return [
+                            ...n,
+                            e
+                        ]
+                    } else {
+                        return n;
+                    }
+                });
+            };
+
+            if (!options.leaveOpen) {
+                sub.OnEnd = (c) => {
+                    c.RemoveSubscription(sub.Id);
+                    if (sub.IsFinished()) {
+                        System.RemoveSubscription(sub.Id);
+                    }
+                };
+            }
+
+            System.AddSubscription(sub);
+            return () => {
+                System.RemoveSubscription(sub.Id);
+            };
+        }
+    }, [sub]);
+
+    return { notes, sub };
+}