when in pool, automatically and efficiently deduplicate.

pool.test.js

@@ -0,0 +1,84 @@
+/* eslint-env jest */
+
+require('websocket-polyfill')
+const {
+  pool,
+  generatePrivateKey,
+  getPublicKey,
+  getEventHash,
+  signEvent
+} = require('./lib/nostr.cjs')
+
+let p = pool()
+
+let relays = [
+  p.ensureRelay('wss://nostr-dev.wellorder.net/'),
+  p.ensureRelay('wss://relay.nostr.bg/'),
+  p.ensureRelay('wss://nostr.fmt.wiz.biz/'),
+  p.ensureRelay('wss://relay.nostr.band/'),
+  p.ensureRelay('wss://nostr.zebedee.cloud/')
+]
+
+beforeAll(async () => {
+  Promise.all(
+    relays.map(relay => {
+      try {
+        return relay.connect()
+      } catch (err) {
+        /***/
+      }
+    })
+  )
+})
+
+afterAll(async () => {
+  relays.forEach(relay => {
+    try {
+      relay.close()
+    } catch (err) {
+      /***/
+    }
+  })
+})
+
+test('removing duplicates when querying', async () => {
+  let priv = generatePrivateKey()
+  let pub = getPublicKey(priv)
+
+  let subs = relays.map(relay =>
+    relay.sub([
+      {
+        authors: [pub]
+      }
+    ])
+  )
+
+  let received = []
+
+  subs.forEach(sub =>
+    sub.on('event', event => {
+      // this should be called only once even though we're listening
+      // to multiple relays because the events will be catched and
+      // deduplicated efficiently (without even being parsed)
+      received.push(event)
+    })
+  )
+
+  let event = {
+    pubkey: pub,
+    created_at: Math.round(Date.now() / 1000),
+    content: 'test',
+    kind: 22345,
+    tags: []
+  }
+  event.id = getEventHash(event)
+  event.sig = signEvent(event, priv)
+
+  relays.forEach(relay => {
+    relay.publish(event)
+  })
+
+  await new Promise(resolve => setTimeout(resolve, 1500))
+
+  return expect(received).toHaveLength(1)
+})

pool.ts

@@ -1,5 +1,8 @@
 import {Relay, relayInit} from './relay'
 import {normalizeURL} from './utils'
+import {Filter} from './filter'
+import {Event} from './event'
+import {SubscriptionOptions, Sub} from './relay'
 
 export function pool(defaultRelays: string[] = []) {
   return new SimplePool(defaultRelays)
@@ -22,6 +25,14 @@ class SimplePool {
     const hasEventId = (id: string): boolean => this._knownIds.has(id)
     const relay = relayInit(nm, hasEventId)
     this._conn[nm] = relay
+
+    let sub = relay.sub
+    relay.sub = (filters: Filter[], opts?: SubscriptionOptions): Sub => {
+      let s = sub(filters, opts)
+      s.on('event', (event: Event) => this._knownIds.add(event.id as string))
+      return s
+    }
+
     return relay
   }
 }

relay.ts

@@ -27,7 +27,7 @@ export type Sub = {
   off: (type: 'event' | 'eose', cb: any) => void
 }
 
-type SubscriptionOptions = {
+export type SubscriptionOptions = {
   skipVerification?: boolean
   id?: string
 }