Add support for nip-26 delegations

filter.test.ts

@@ -144,6 +144,26 @@ describe('Filter', () => {
 
       expect(result).toEqual(true)
     })
+
+    it('should return true when the event delegator is in the filter', () => {
+      const filter = { author: ['abc'] }
+
+      const event = buildEvent({ pubkey: 'def', tags: [['delegation', 'abc', '', '']] })
+
+      const result = matchFilter(filter, event)
+
+      expect(result).toEqual(true)
+    })
+
+    it('should return true when the event delegator prefix is in the filter', () => {
+      const filter = { author: ['a'] }
+
+      const event = buildEvent({ pubkey: 'def', tags: [['delegation', 'abc', '', '']] })
+
+      const result = matchFilter(filter, event)
+
+      expect(result).toEqual(true)
+    })
   })
 
   describe('matchFilters', () => {

filter.ts

@@ -17,9 +17,17 @@ export function matchFilter(filter: Filter<number>, event: Event<number>): boole
       return false
     }
   }
+  const d_pubkey: string = event.tags.find(tag => tag[0] === 'delegation')?.at(1) ?? ''
   if (filter.kinds && filter.kinds.indexOf(event.kind) === -1) return false
-  if (filter.authors && filter.authors.indexOf(event.pubkey) === -1) {
-    if (!filter.authors.some(prefix => event.pubkey.startsWith(prefix))) {
+  if (
+    filter.authors &&
+    filter.authors.indexOf(event.pubkey) === -1 &&
+    (d_pubkey === '' || filter.authors.indexOf(d_pubkey) === -1)
+  ) {
+    if (
+      !filter.authors.some(prefix => event.pubkey.startsWith(prefix)) &&
+      (d_pubkey === '' || !filter.authors.some(prefix => d_pubkey.startsWith(prefix)))
+    ) {
       return false
     }
   }