From cec35dcb60fe1ef41a3429972c411853449cc0d7 Mon Sep 17 00:00:00 2001
From: Truman Gao <106889354+tdgao@users.noreply.github.com>
Date: Mon, 9 Feb 2026 16:37:58 -0700
Subject: [PATCH] fix: project card preload on hover (#5348)

---
 .../src/pages/discover/[type]/index.vue       | 30 +++++++++++--------
 .../components/project/card/ProjectCard.vue   |  6 ++--
 2 files changed, 21 insertions(+), 15 deletions(-)

diff --git a/apps/frontend/src/pages/discover/[type]/index.vue b/apps/frontend/src/pages/discover/[type]/index.vue
index 56609a384..bf3b4b670 100644
--- a/apps/frontend/src/pages/discover/[type]/index.vue
+++ b/apps/frontend/src/pages/discover/[type]/index.vue
@@ -37,7 +37,7 @@ import {
 } from '@modrinth/ui'
 import { capitalizeString, cycleValue, type Mod as InstallableMod } from '@modrinth/utils'
 import { useQueryClient } from '@tanstack/vue-query'
-import { useThrottleFn } from '@vueuse/core'
+import { useThrottleFn, useTimeoutFn } from '@vueuse/core'
 import { computed, type Reactive, watch } from 'vue'
 
 import LogoAnimated from '~/components/brand/LogoAnimated.vue'
@@ -63,18 +63,21 @@ const { handleError } = injectNotificationManager()
 const modrinthClient = injectModrinthClient()
 const queryClient = useQueryClient()
 
-let prefetchTimeout: ReturnType<typeof setTimeout> | null = null
+let prefetchTimeout: ReturnType<typeof useTimeoutFn> | null = null
+const HOVER_DURATION_TO_PREFETCH_MS = 500
 
-function handleProjectHover(result: Labrinth.Search.v2.ResultSearchProject) {
-	if (prefetchTimeout) clearTimeout(prefetchTimeout)
-	prefetchTimeout = setTimeout(() => {
-		const slug = result.slug || result.project_id
-		queryClient.prefetchQuery(projectQueryOptions.v2(slug, modrinthClient))
-		queryClient.prefetchQuery(projectQueryOptions.v3(result.project_id, modrinthClient))
-		queryClient.prefetchQuery(projectQueryOptions.members(result.project_id, modrinthClient))
-		queryClient.prefetchQuery(projectQueryOptions.dependencies(result.project_id, modrinthClient))
-		queryClient.prefetchQuery(projectQueryOptions.versionsV3(result.project_id, modrinthClient))
-	}, 150)
+const handleProjectMouseEnter = (result: Labrinth.Search.v2.ResultSearchProject) => {
+	const slug = result.slug || result.project_id
+	prefetchTimeout = useTimeoutFn(
+		() => queryClient.prefetchQuery(projectQueryOptions.v2(slug, modrinthClient)),
+		HOVER_DURATION_TO_PREFETCH_MS,
+		{ immediate: false },
+	)
+	prefetchTimeout.start()
+}
+
+const handleProjectHoverEnd = () => {
+	if (prefetchTimeout) prefetchTimeout.stop()
 }
 
 const currentType = computed(() =>
@@ -694,7 +697,8 @@ useSeoMeta({
 						:layout="
 							resultsDisplayMode === 'grid' || resultsDisplayMode === 'gallery' ? 'grid' : 'list'
 						"
-						@hover="handleProjectHover(result)"
+						@mouseenter="handleProjectMouseEnter(result)"
+						@mouseleave="handleProjectHoverEnd"
 					>
 						<template v-if="flags.showDiscoverProjectButtons || server" #actions>
 							<template v-if="flags.showDiscoverProjectButtons">
diff --git a/packages/ui/src/components/project/card/ProjectCard.vue b/packages/ui/src/components/project/card/ProjectCard.vue
index 0b621436c..8b0a3519d 100644
--- a/packages/ui/src/components/project/card/ProjectCard.vue
+++ b/packages/ui/src/components/project/card/ProjectCard.vue
@@ -4,7 +4,8 @@
 			<AutoLink
 				:to="link"
 				class="rounded-xl no-outline no-click-animation custom-focus-indicator"
-				@mouseenter="$emit('hover')"
+				@mouseenter="$emit('mouseenter')"
+				@mouseleave="$emit('mouseleave')"
 			></AutoLink>
 		</template>
 		<div v-if="layout === 'grid'" :class="[baseCardStyle, 'flex flex-col']">
@@ -153,7 +154,8 @@ import ProjectCardTags from './ProjectCardTags.vue'
 import ProjectCardTitle from './ProjectCardTitle.vue'
 
 defineEmits<{
-	hover: []
+	mouseenter: []
+	mouseleave: []
 }>()
 
 const props = defineProps<{