feat: add useEventReactions to system-react

packages/system-react/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@snort/system-react",
-  "version": "1.0.16",
+  "version": "1.0.17",
   "description": "React hooks for @snort/system",
   "main": "dist/index.js",
   "types": "dist/index.d.ts",
@@ -15,7 +15,7 @@
     "dist"
   ],
   "dependencies": {
-    "@snort/shared": "^1.0.7",
+    "@snort/shared": "^1.0.8",
     "@snort/system": "^1.0.22",
     "react": "^18.2.0"
   },

packages/system-react/src/index.ts

@@ -1,5 +1,7 @@
+export * from "./context";
+
 export * from "./useRequestBuilder";
 export * from "./useSystemState";
 export * from "./useUserProfile";
-export * from "./context";
 export * from "./useUserSearch";
+export * from "./useEventReactions";

packages/system-react/src/useEventReactions.tsx

@@ -0,0 +1,55 @@
+import { useContext, useMemo } from "react";
+import { normalizeReaction, Reaction } from "@snort/shared";
+import { EventKind, NostrLink, parseZap, TaggedNostrEvent } from "@snort/system";
+
+import { SnortContext } from "./context";
+
+/**
+ * Parse reactions to a given event from a set of related events
+ * @param ev 
+ * @param related 
+ * @returns 
+ */
+export function useEventReactions(ev: TaggedNostrEvent, related: ReadonlyArray<TaggedNostrEvent>) {
+  const system = useContext(SnortContext);
+
+  return useMemo(() => {
+    const link = NostrLink.fromEvent(ev);
+    const reactionKinds = related.reduce((acc, v) => {
+      if (link.isReplyToThis(v)) {
+        acc[v.kind.toString()] ??= [];
+        acc[v.kind.toString()].push(v);
+      }
+      return acc;
+    }, {} as Record<string, Array<TaggedNostrEvent>>);
+
+    const deletions = reactionKinds[EventKind.Deletion.toString()] ?? [];
+    const reactions = reactionKinds[EventKind.Reaction.toString()] ?? [];
+    const reposts = reactionKinds[EventKind.Repost.toString()] ?? [];
+
+    const groupReactions = reactions?.reduce((acc, reaction) => {
+      const kind = normalizeReaction(reaction.content);
+      acc[kind] ??= [];
+      acc[kind].push(reaction);
+      return acc;
+    }, {} as Record<Reaction, Array<TaggedNostrEvent>>);
+
+    const zaps = (reactionKinds[EventKind.ZapReceipt] ?? [])
+      .map(a => parseZap(a, system.ProfileLoader.Cache, ev))
+      .filter(a => a.valid)
+      .sort((a, b) => b.amount - a.amount);
+
+    return {
+      deletions,
+      reactions: {
+        positive: groupReactions[Reaction.Positive], 
+        negative: groupReactions[Reaction.Negative],
+      },
+      reposts,
+      zaps,
+      others: Object.fromEntries(
+        Object.entries(reactionKinds)
+          .filter(([k]) => ![EventKind.Deletion, EventKind.Reaction, EventKind.Repost, EventKind.ZapReceipt].includes(Number(k))))
+    };
+  }, [ev, related]);
+}