From a55fb8465fb2b96dcbce61ec789759bf49ad4013 Mon Sep 17 00:00:00 2001
From: fiatjaf <fiatjaf@gmail.com>
Date: Fri, 9 Jun 2023 23:00:57 -0300
Subject: [PATCH] mergeFilters()

---
 filter.test.ts | 37 +++++++++++++++++++++++++++++++++----
 filter.ts      | 34 ++++++++++++++++++++++++++++++++++
 package.json   |  2 +-
 3 files changed, 68 insertions(+), 5 deletions(-)

diff --git a/filter.test.ts b/filter.test.ts
index 35744ec..b7f9cea 100644
--- a/filter.test.ts
+++ b/filter.test.ts
@@ -1,4 +1,4 @@
-import {matchFilter, matchFilters} from './filter.ts'
+import {matchFilter, matchFilters, mergeFilters} from './filter.ts'
 import {buildEvent} from './test-helpers.ts'
 
 describe('Filter', () => {
@@ -18,7 +18,7 @@ describe('Filter', () => {
         kind: 1,
         pubkey: 'abc',
         created_at: 150,
-        tags: [['tag', 'value']],
+        tags: [['tag', 'value']]
       })
 
       const result = matchFilter(filter, event)
@@ -162,7 +162,12 @@ describe('Filter', () => {
         {authors: ['abc'], limit: 3}
       ]
 
-      const event = buildEvent({id: '123', kind: 1, pubkey: 'abc', created_at: 150})
+      const event = buildEvent({
+        id: '123',
+        kind: 1,
+        pubkey: 'abc',
+        created_at: 150
+      })
 
       const result = matchFilters(filters, event)
 
@@ -189,11 +194,35 @@ describe('Filter', () => {
         {kinds: [1], limit: 2},
         {authors: ['abc'], limit: 3}
       ]
-      const event = buildEvent({id: '456', kind: 2, pubkey: 'def', created_at: 200})
+      const event = buildEvent({
+        id: '456',
+        kind: 2,
+        pubkey: 'def',
+        created_at: 200
+      })
 
       const result = matchFilters(filters, event)
 
       expect(result).toEqual(false)
     })
   })
+
+  describe('mergeFilters', () => {
+    it('should merge filters', () => {
+      expect(
+        mergeFilters(
+          {ids: ['a', 'b'], limit: 3},
+          {authors: ['x'], ids: ['b', 'c']}
+        )
+      ).toEqual({ids: ['a', 'b', 'c'], limit: 3, authors: ['x']})
+
+      expect(
+        mergeFilters(
+          {kinds: [1], since: 15, until: 30},
+          {since: 10, kinds: [7], until: 15},
+          {kinds: [9, 10]}
+        )
+      ).toEqual({kinds: [1, 7, 9, 10], since: 10, until: 30})
+    })
+  })
 })
diff --git a/filter.ts b/filter.ts
index f233a34..d6fe610 100644
--- a/filter.ts
+++ b/filter.ts
@@ -56,3 +56,37 @@ export function matchFilters(
   }
   return false
 }
+
+export function mergeFilters(...filters: Filter<number>[]): Filter<number> {
+  let result: Filter<number> = {}
+  for (let i = 0; i < filters.length; i++) {
+    let filter = filters[i]
+    Object.entries(filter).forEach(([property, values]) => {
+      if (
+        property === 'kinds' ||
+        property === 'ids' ||
+        property === 'authors' ||
+        property[0] === '#'
+      ) {
+        // @ts-ignore
+        result[property] = result[property] || []
+        // @ts-ignore
+        for (let v = 0; v < values.length; v++) {
+          // @ts-ignore
+          let value = values[v]
+          // @ts-ignore
+          if (!result[property].includes(value)) result[property].push(value)
+        }
+      }
+    })
+
+    if (filter.limit && (!result.limit || filter.limit > result.limit))
+      result.limit = filter.limit
+    if (filter.until && (!result.until || filter.until > result.until))
+      result.until = filter.until
+    if (filter.since && (!result.since || filter.since < result.since))
+      result.since = filter.since
+  }
+
+  return result
+}
diff --git a/package.json b/package.json
index 79fc0c0..dc028c2 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "nostr-tools",
-  "version": "1.11.2",
+  "version": "1.12.0",
   "description": "Tools for making a Nostr client.",
   "repository": {
     "type": "git",