From 4bfdd92b65c1094ebf5eb361023b102104d1b4df Mon Sep 17 00:00:00 2001
From: dawn <90008@gaze.systems>
Date: Wed, 7 Jan 2026 07:42:15 +0300
Subject: [PATCH] on other user profiles, only fetch thread chains upwards, not
 downwards

---
 src/components/ProfileView.svelte  |  1 +
 src/components/TimelineView.svelte |  4 ++-
 src/lib/at/fetch.ts                | 57 +++++++++++++++++-------------
 src/lib/state.svelte.ts            | 13 +++++--
 4 files changed, 46 insertions(+), 29 deletions(-)

diff --git a/src/components/ProfileView.svelte b/src/components/ProfileView.svelte
index 8463dee..669fcd1 100644
--- a/src/components/ProfileView.svelte
+++ b/src/components/ProfileView.svelte
@@ -146,6 +146,7 @@
 					</div>
 
 					<TimelineView
+						hydrateOptions={{ downwards: 'none' }}
 						showReplies={false}
 						{client}
 						targetDid={did}
diff --git a/src/components/TimelineView.svelte b/src/components/TimelineView.svelte
index dce9d22..6f7b480 100644
--- a/src/components/TimelineView.svelte
+++ b/src/components/TimelineView.svelte
@@ -63,7 +63,9 @@
 		loaderState.status = 'LOADING';
 
 		try {
-			await fetchTimeline(client, did, 7, showReplies);
+			await fetchTimeline(client, did, 7, showReplies, {
+				downwards: userDid === did ? 'sameAuthor' : 'none'
+			});
 			// only fetch interactions if logged in (because if not who is the interactor)
 			if (client.user && userDid) {
 				if (!fetchingInteractions) {
diff --git a/src/lib/at/fetch.ts b/src/lib/at/fetch.ts
index 21f49b2..b4e9ce1 100644
--- a/src/lib/at/fetch.ts
+++ b/src/lib/at/fetch.ts
@@ -59,11 +59,16 @@ export const fetchPosts = async (
 	}
 };
 
+export type HydrateOptions = {
+	downwards: 'sameAuthor' | 'none';
+};
+
 export const hydratePosts = async (
 	client: AtpClient,
 	repo: Did,
 	data: PostWithBacklinks[],
-	cacheFn: (did: Did, rkey: RecordKey) => Ok<PostWithUri> | undefined
+	cacheFn: (did: Did, rkey: RecordKey) => Ok<PostWithUri> | undefined,
+	options?: Partial<HydrateOptions>
 ): Promise<Result<Map<ResourceUri, PostWithUri>, string>> => {
 	let posts: Map<ResourceUri, PostWithUri> = new Map();
 	try {
@@ -115,33 +120,35 @@ export const hydratePosts = async (
 	};
 	await Promise.all(posts.values().map(fetchUpwardsChain));
 
-	try {
-		const fetchDownwardsChain = async (post: PostWithUri) => {
-			const { repo: postRepo } = expect(parseCanonicalResourceUri(post.uri));
-			if (repo === postRepo) return;
+	if (options?.downwards !== 'none') {
+		try {
+			const fetchDownwardsChain = async (post: PostWithUri) => {
+				const { repo: postRepo } = expect(parseCanonicalResourceUri(post.uri));
+				if (repo === postRepo) return;
 
-			// get chains that are the same author until we exhaust them
-			const backlinks = await client.getBacklinks(post.uri, replySource);
-			if (!backlinks.ok) return;
+				// get chains that are the same author until we exhaust them
+				const backlinks = await client.getBacklinks(post.uri, replySource);
+				if (!backlinks.ok) return;
 
-			const promises = [];
-			for (const reply of backlinks.value.records) {
-				if (reply.did !== postRepo) continue;
-				// if we already have this reply, then we already fetched this chain / are fetching it
-				if (posts.has(toCanonicalUri(reply))) continue;
-				const record =
-					cacheFn(reply.did, reply.rkey) ??
-					(await client.getRecord(AppBskyFeedPost.mainSchema, reply.did, reply.rkey));
-				if (!record.ok) break; // TODO: this doesnt handle deleted posts in between
-				posts.set(record.value.uri, record.value);
-				promises.push(fetchDownwardsChain(record.value));
-			}
+				const promises = [];
+				for (const reply of backlinks.value.records) {
+					if (reply.did !== postRepo) continue;
+					// if we already have this reply, then we already fetched this chain / are fetching it
+					if (posts.has(toCanonicalUri(reply))) continue;
+					const record =
+						cacheFn(reply.did, reply.rkey) ??
+						(await client.getRecord(AppBskyFeedPost.mainSchema, reply.did, reply.rkey));
+					if (!record.ok) break; // TODO: this doesnt handle deleted posts in between
+					posts.set(record.value.uri, record.value);
+					promises.push(fetchDownwardsChain(record.value));
+				}
 
-			await Promise.all(promises);
-		};
-		await Promise.all(posts.values().map(fetchDownwardsChain));
-	} catch (error) {
-		return err(`cant fetch post reply chain: ${error}`);
+				await Promise.all(promises);
+			};
+			await Promise.all(posts.values().map(fetchDownwardsChain));
+		} catch (error) {
+			return err(`cant fetch post reply chain: ${error}`);
+		}
 	}
 
 	return ok(posts);
diff --git a/src/lib/state.svelte.ts b/src/lib/state.svelte.ts
index e757a53..6819e27 100644
--- a/src/lib/state.svelte.ts
+++ b/src/lib/state.svelte.ts
@@ -7,7 +7,7 @@ import {
 } from './at/client.svelte';
 import { SvelteMap, SvelteDate, SvelteSet } from 'svelte/reactivity';
 import type { Did, Handle, Nsid, RecordKey, ResourceUri } from '@atcute/lexicons';
-import { fetchPosts, hydratePosts, type PostWithUri } from './at/fetch';
+import { fetchPosts, hydratePosts, type HydrateOptions, type PostWithUri } from './at/fetch';
 import { parseCanonicalResourceUri, type AtprotoDid } from '@atcute/lexicons/syntax';
 import {
 	AppBskyActorProfile,
@@ -479,7 +479,8 @@ export const fetchTimeline = async (
 	client: AtpClient,
 	subject: Did,
 	limit: number = 6,
-	withBacklinks: boolean = true
+	withBacklinks: boolean = true,
+	hydrateOptions?: Partial<HydrateOptions>
 ) => {
 	const cursor = postCursors.get(subject);
 	if (cursor && cursor.end) return;
@@ -490,7 +491,13 @@ export const fetchTimeline = async (
 	// if the cursor is undefined, we've reached the end of the timeline
 	const newCursor = { value: accPosts.value.cursor, end: !accPosts.value.cursor };
 	postCursors.set(subject, newCursor);
-	const hydrated = await hydratePosts(client, subject, accPosts.value.posts, hydrateCacheFn);
+	const hydrated = await hydratePosts(
+		client,
+		subject,
+		accPosts.value.posts,
+		hydrateCacheFn,
+		hydrateOptions
+	);
 	if (!hydrated.ok) throw `cant hydrate posts ${subject}: ${hydrated.error}`;
 
 	addPosts(hydrated.value.values());
-- 
2.51.2