diff --git a/packages/frontend/lib/rollup-plugin-unwind-css-module-class-name.test.ts b/packages/frontend/lib/rollup-plugin-unwind-css-module-class-name.test.ts
index 550e08d7f7..535adc9c85 100644
--- a/packages/frontend/lib/rollup-plugin-unwind-css-module-class-name.test.ts
+++ b/packages/frontend/lib/rollup-plugin-unwind-css-module-class-name.test.ts
@@ -6,7 +6,7 @@
 import { parse } from 'acorn';
 import { generate } from 'astring';
 import { describe, expect, it } from 'vitest';
-import { normalizeClass, unwindCssModuleClassName } from './rollup-plugin-unwind-css-module-class-name';
+import { normalizeClass, unwindCssModuleClassName } from './rollup-plugin-unwind-css-module-class-name.js';
 import type * as estree from 'estree';
 
 function parseExpression(code: string): estree.Expression {
diff --git a/packages/frontend/src/components/MkAbuseReport.stories.impl.ts b/packages/frontend/src/components/MkAbuseReport.stories.impl.ts
index 3b64529620..77e7c84d5c 100644
--- a/packages/frontend/src/components/MkAbuseReport.stories.impl.ts
+++ b/packages/frontend/src/components/MkAbuseReport.stories.impl.ts
@@ -7,8 +7,8 @@
 import { action } from '@storybook/addon-actions';
 import { StoryObj } from '@storybook/vue3';
 import { rest } from 'msw';
-import { abuseUserReport } from '../../.storybook/fakes';
-import { commonHandlers } from '../../.storybook/mocks';
+import { abuseUserReport } from '../../.storybook/fakes.js';
+import { commonHandlers } from '../../.storybook/mocks.js';
 import MkAbuseReport from './MkAbuseReport.vue';
 export const Default = {
 	render(args) {
diff --git a/packages/frontend/src/components/MkAbuseReportWindow.stories.impl.ts b/packages/frontend/src/components/MkAbuseReportWindow.stories.impl.ts
index b45d54679b..dc842b3d1b 100644
--- a/packages/frontend/src/components/MkAbuseReportWindow.stories.impl.ts
+++ b/packages/frontend/src/components/MkAbuseReportWindow.stories.impl.ts
@@ -7,8 +7,8 @@
 import { action } from '@storybook/addon-actions';
 import { StoryObj } from '@storybook/vue3';
 import { rest } from 'msw';
-import { userDetailed } from '../../.storybook/fakes';
-import { commonHandlers } from '../../.storybook/mocks';
+import { userDetailed } from '../../.storybook/fakes.js';
+import { commonHandlers } from '../../.storybook/mocks.js';
 import MkAbuseReportWindow from './MkAbuseReportWindow.vue';
 export const Default = {
 	render(args) {
diff --git a/packages/frontend/src/components/MkAccountMoved.stories.impl.ts b/packages/frontend/src/components/MkAccountMoved.stories.impl.ts
index a6d4d18c1b..33c6c24631 100644
--- a/packages/frontend/src/components/MkAccountMoved.stories.impl.ts
+++ b/packages/frontend/src/components/MkAccountMoved.stories.impl.ts
@@ -5,7 +5,7 @@
 
 /* eslint-disable @typescript-eslint/explicit-function-return-type */
 import { StoryObj } from '@storybook/vue3';
-import { userDetailed } from '../../.storybook/fakes';
+import { userDetailed } from '../../.storybook/fakes.js';
 import MkAccountMoved from './MkAccountMoved.vue';
 export const Default = {
 	render(args) {
diff --git a/packages/frontend/src/components/MkAchievements.stories.impl.ts b/packages/frontend/src/components/MkAchievements.stories.impl.ts
index a67e1def13..6d972467b1 100644
--- a/packages/frontend/src/components/MkAchievements.stories.impl.ts
+++ b/packages/frontend/src/components/MkAchievements.stories.impl.ts
@@ -6,8 +6,8 @@
 /* eslint-disable @typescript-eslint/explicit-function-return-type */
 import { StoryObj } from '@storybook/vue3';
 import { rest } from 'msw';
-import { userDetailed } from '../../.storybook/fakes';
-import { commonHandlers } from '../../.storybook/mocks';
+import { userDetailed } from '../../.storybook/fakes.js';
+import { commonHandlers } from '../../.storybook/mocks.js';
 import MkAchievements from './MkAchievements.vue';
 import { ACHIEVEMENT_TYPES } from '@/scripts/achievements.js';
 export const Empty = {
diff --git a/packages/frontend/src/components/MkAutocomplete.stories.impl.ts b/packages/frontend/src/components/MkAutocomplete.stories.impl.ts
index 8232759ba0..969519386f 100644
--- a/packages/frontend/src/components/MkAutocomplete.stories.impl.ts
+++ b/packages/frontend/src/components/MkAutocomplete.stories.impl.ts
@@ -9,8 +9,8 @@ import { expect } from '@storybook/jest';
 import { userEvent, waitFor, within } from '@storybook/testing-library';
 import { StoryObj } from '@storybook/vue3';
 import { rest } from 'msw';
-import { userDetailed } from '../../.storybook/fakes';
-import { commonHandlers } from '../../.storybook/mocks';
+import { userDetailed } from '../../.storybook/fakes.js';
+import { commonHandlers } from '../../.storybook/mocks.js';
 import MkAutocomplete from './MkAutocomplete.vue';
 import MkInput from './MkInput.vue';
 import { tick } from '@/scripts/test-utils.js';
diff --git a/packages/frontend/src/components/MkAvatars.stories.impl.ts b/packages/frontend/src/components/MkAvatars.stories.impl.ts
index 659c0eebdf..d41b64695f 100644
--- a/packages/frontend/src/components/MkAvatars.stories.impl.ts
+++ b/packages/frontend/src/components/MkAvatars.stories.impl.ts
@@ -6,8 +6,8 @@
 /* eslint-disable @typescript-eslint/explicit-function-return-type */
 import { StoryObj } from '@storybook/vue3';
 import { rest } from 'msw';
-import { userDetailed } from '../../.storybook/fakes';
-import { commonHandlers } from '../../.storybook/mocks';
+import { userDetailed } from '../../.storybook/fakes.js';
+import { commonHandlers } from '../../.storybook/mocks.js';
 import MkAvatars from './MkAvatars.vue';
 export const Default = {
 	render(args) {
diff --git a/packages/frontend/src/components/MkContextMenu.vue b/packages/frontend/src/components/MkContextMenu.vue
index b78252be89..e29cf472f7 100644
--- a/packages/frontend/src/components/MkContextMenu.vue
+++ b/packages/frontend/src/components/MkContextMenu.vue
@@ -20,7 +20,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 <script lang="ts" setup>
 import { onMounted, onBeforeUnmount, shallowRef, ref } from 'vue';
 import MkMenu from './MkMenu.vue';
-import { MenuItem } from './types/menu.vue';
+import { MenuItem } from '@/types/menu.js';
 import contains from '@/scripts/contains.js';
 import { defaultStore } from '@/store.js';
 import * as os from '@/os.js';
diff --git a/packages/frontend/src/components/MkDateSeparatedList.vue b/packages/frontend/src/components/MkDateSeparatedList.vue
index e5bdd3781b..0a71b689fe 100644
--- a/packages/frontend/src/components/MkDateSeparatedList.vue
+++ b/packages/frontend/src/components/MkDateSeparatedList.vue
@@ -6,11 +6,11 @@ SPDX-License-Identifier: AGPL-3.0-only
 <script lang="ts">
 import { defineComponent, h, PropType, TransitionGroup, useCssModule } from 'vue';
 import MkAd from '@/components/global/MkAd.vue';
-import { isDebuggerEnabled, stackTraceInstances } from '@/debug';
+import { isDebuggerEnabled, stackTraceInstances } from '@/debug.js';
 import { i18n } from '@/i18n.js';
 import * as os from '@/os.js';
 import { defaultStore } from '@/store.js';
-import { MisskeyEntity } from '@/types/date-separated-list';
+import { MisskeyEntity } from '@/types/date-separated-list.js';
 
 export default defineComponent({
 	props: {
diff --git a/packages/frontend/src/components/MkGalleryPostPreview.stories.impl.ts b/packages/frontend/src/components/MkGalleryPostPreview.stories.impl.ts
index 29e27e1373..035b727a35 100644
--- a/packages/frontend/src/components/MkGalleryPostPreview.stories.impl.ts
+++ b/packages/frontend/src/components/MkGalleryPostPreview.stories.impl.ts
@@ -7,7 +7,7 @@
 import { expect } from '@storybook/jest';
 import { userEvent, waitFor, within } from '@storybook/testing-library';
 import { StoryObj } from '@storybook/vue3';
-import { galleryPost } from '../../.storybook/fakes';
+import { galleryPost } from '../../.storybook/fakes.js';
 import MkGalleryPostPreview from './MkGalleryPostPreview.vue';
 export const Default = {
 	render(args) {
diff --git a/packages/frontend/src/components/MkInviteCode.stories.impl.ts b/packages/frontend/src/components/MkInviteCode.stories.impl.ts
index 0127ce061b..2ea32dd3b6 100644
--- a/packages/frontend/src/components/MkInviteCode.stories.impl.ts
+++ b/packages/frontend/src/components/MkInviteCode.stories.impl.ts
@@ -6,8 +6,8 @@
 /* eslint-disable @typescript-eslint/explicit-function-return-type */
 import { StoryObj } from '@storybook/vue3';
 import { rest } from 'msw';
-import { userDetailed, inviteCode } from '../../.storybook/fakes';
-import { commonHandlers } from '../../.storybook/mocks';
+import { userDetailed, inviteCode } from '../../.storybook/fakes.js';
+import { commonHandlers } from '../../.storybook/mocks.js';
 import MkInviteCode from './MkInviteCode.vue';
 
 export const Default = {
diff --git a/packages/frontend/src/components/MkMediaList.vue b/packages/frontend/src/components/MkMediaList.vue
index c5be2a2f62..09c5ad9222 100644
--- a/packages/frontend/src/components/MkMediaList.vue
+++ b/packages/frontend/src/components/MkMediaList.vue
@@ -37,7 +37,7 @@ import XBanner from '@/components/MkMediaBanner.vue';
 import XImage from '@/components/MkMediaImage.vue';
 import XVideo from '@/components/MkMediaVideo.vue';
 import * as os from '@/os.js';
-import { FILE_TYPE_BROWSERSAFE } from '@/const';
+import { FILE_TYPE_BROWSERSAFE } from '@/const.js';
 import { defaultStore } from '@/store.js';
 
 const props = defineProps<{
diff --git a/packages/frontend/src/components/MkMenu.vue b/packages/frontend/src/components/MkMenu.vue
index 0a97cf3dba..3026d4f015 100644
--- a/packages/frontend/src/components/MkMenu.vue
+++ b/packages/frontend/src/components/MkMenu.vue
@@ -77,7 +77,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 import { computed, defineAsyncComponent, nextTick, onBeforeUnmount, onMounted, ref, shallowRef, watch } from 'vue';
 import { focusPrev, focusNext } from '@/scripts/focus.js';
 import MkSwitchButton from '@/components/MkSwitch.button.vue';
-import { MenuItem, InnerMenuItem, MenuPending, MenuAction, MenuSwitch, MenuParent } from '@/types/menu';
+import { MenuItem, InnerMenuItem, MenuPending, MenuAction, MenuSwitch, MenuParent } from '@/types/menu.js';
 import * as os from '@/os.js';
 import { i18n } from '@/i18n.js';
 import { isTouchUsing } from '@/scripts/touch.js';
diff --git a/packages/frontend/src/components/MkPageWindow.vue b/packages/frontend/src/components/MkPageWindow.vue
index 23eb70ecd2..2647ace7db 100644
--- a/packages/frontend/src/components/MkPageWindow.vue
+++ b/packages/frontend/src/components/MkPageWindow.vue
@@ -37,7 +37,7 @@ import copyToClipboard from '@/scripts/copy-to-clipboard.js';
 import { url } from '@/config.js';
 import { mainRouter, routes, page } from '@/router.js';
 import { $i } from '@/account.js';
-import { Router, useScrollPositionManager } from '@/nirax';
+import { Router, useScrollPositionManager } from '@/nirax.js';
 import { i18n } from '@/i18n.js';
 import { PageMetadata, provideMetadataReceiver } from '@/scripts/page-metadata.js';
 import { openingWindowsCount } from '@/os.js';
diff --git a/packages/frontend/src/components/MkPagination.vue b/packages/frontend/src/components/MkPagination.vue
index 07347eda29..bdd96238d3 100644
--- a/packages/frontend/src/components/MkPagination.vue
+++ b/packages/frontend/src/components/MkPagination.vue
@@ -49,7 +49,7 @@ import * as os from '@/os.js';
 import { onScrollTop, isTopVisible, getBodyScrollHeight, getScrollContainer, onScrollBottom, scrollToBottom, scroll, isBottomVisible } from '@/scripts/scroll.js';
 import { useDocumentVisibility } from '@/scripts/use-document-visibility.js';
 import { defaultStore } from '@/store.js';
-import { MisskeyEntity } from '@/types/date-separated-list';
+import { MisskeyEntity } from '@/types/date-separated-list.js';
 import { i18n } from '@/i18n.js';
 
 const SECOND_FETCH_LIMIT = 30;
diff --git a/packages/frontend/src/components/MkUserSetupDialog.Follow.stories.impl.ts b/packages/frontend/src/components/MkUserSetupDialog.Follow.stories.impl.ts
index 9122bb8983..45c7da40ce 100644
--- a/packages/frontend/src/components/MkUserSetupDialog.Follow.stories.impl.ts
+++ b/packages/frontend/src/components/MkUserSetupDialog.Follow.stories.impl.ts
@@ -6,8 +6,8 @@
 /* eslint-disable @typescript-eslint/explicit-function-return-type */
 import { StoryObj } from '@storybook/vue3';
 import { rest } from 'msw';
-import { commonHandlers } from '../../.storybook/mocks';
-import { userDetailed } from '../../.storybook/fakes';
+import { commonHandlers } from '../../.storybook/mocks.js';
+import { userDetailed } from '../../.storybook/fakes.js';
 import MkUserSetupDialog_Follow from './MkUserSetupDialog.Follow.vue';
 export const Default = {
 	render(args) {
diff --git a/packages/frontend/src/components/MkUserSetupDialog.User.stories.impl.ts b/packages/frontend/src/components/MkUserSetupDialog.User.stories.impl.ts
index 3324c0186c..31176c0832 100644
--- a/packages/frontend/src/components/MkUserSetupDialog.User.stories.impl.ts
+++ b/packages/frontend/src/components/MkUserSetupDialog.User.stories.impl.ts
@@ -5,7 +5,7 @@
 
 /* eslint-disable @typescript-eslint/explicit-function-return-type */
 import { StoryObj } from '@storybook/vue3';
-import { userDetailed } from '../../.storybook/fakes';
+import { userDetailed } from '../../.storybook/fakes.js';
 import MkUserSetupDialog_User from './MkUserSetupDialog.User.vue';
 export const Default = {
 	render(args) {
diff --git a/packages/frontend/src/components/MkUserSetupDialog.stories.impl.ts b/packages/frontend/src/components/MkUserSetupDialog.stories.impl.ts
index 2795bcb2fa..5182db12b2 100644
--- a/packages/frontend/src/components/MkUserSetupDialog.stories.impl.ts
+++ b/packages/frontend/src/components/MkUserSetupDialog.stories.impl.ts
@@ -6,8 +6,8 @@
 /* eslint-disable @typescript-eslint/explicit-function-return-type */
 import { StoryObj } from '@storybook/vue3';
 import { rest } from 'msw';
-import { commonHandlers } from '../../.storybook/mocks';
-import { userDetailed } from '../../.storybook/fakes';
+import { commonHandlers } from '../../.storybook/mocks.js';
+import { userDetailed } from '../../.storybook/fakes.js';
 import MkUserSetupDialog from './MkUserSetupDialog.vue';
 export const Default = {
 	render(args) {
diff --git a/packages/frontend/src/components/MkWidgets.vue b/packages/frontend/src/components/MkWidgets.vue
index e2d7ceab7b..dc7c8bd06b 100644
--- a/packages/frontend/src/components/MkWidgets.vue
+++ b/packages/frontend/src/components/MkWidgets.vue
@@ -54,7 +54,7 @@ import { defineAsyncComponent, ref } from 'vue';
 import { v4 as uuid } from 'uuid';
 import MkSelect from '@/components/MkSelect.vue';
 import MkButton from '@/components/MkButton.vue';
-import { widgets as widgetDefs } from '@/widgets';
+import { widgets as widgetDefs } from '@/widgets/index.js';
 import * as os from '@/os.js';
 import { i18n } from '@/i18n.js';
 
diff --git a/packages/frontend/src/components/global/MkAcct.stories.impl.ts b/packages/frontend/src/components/global/MkAcct.stories.impl.ts
index 00c1d94330..49ec61211c 100644
--- a/packages/frontend/src/components/global/MkAcct.stories.impl.ts
+++ b/packages/frontend/src/components/global/MkAcct.stories.impl.ts
@@ -5,7 +5,7 @@
 
 /* eslint-disable @typescript-eslint/explicit-function-return-type */
 import { StoryObj } from '@storybook/vue3';
-import { userDetailed } from '../../../.storybook/fakes';
+import { userDetailed } from '../../../.storybook/fakes.js';
 import MkAcct from './MkAcct.vue';
 export const Default = {
 	render(args) {
diff --git a/packages/frontend/src/components/global/MkAvatar.stories.impl.ts b/packages/frontend/src/components/global/MkAvatar.stories.impl.ts
index 877511f8fc..515d7eab18 100644
--- a/packages/frontend/src/components/global/MkAvatar.stories.impl.ts
+++ b/packages/frontend/src/components/global/MkAvatar.stories.impl.ts
@@ -5,7 +5,7 @@
 
 /* eslint-disable @typescript-eslint/explicit-function-return-type */
 import { StoryObj } from '@storybook/vue3';
-import { userDetailed } from '../../../.storybook/fakes';
+import { userDetailed } from '../../../.storybook/fakes.js';
 import MkAvatar from './MkAvatar.vue';
 const common = {
 	render(args) {
diff --git a/packages/frontend/src/components/global/MkMisskeyFlavoredMarkdown.stories.impl.ts b/packages/frontend/src/components/global/MkMisskeyFlavoredMarkdown.stories.impl.ts
index 9d9febf693..9cdb490e4b 100644
--- a/packages/frontend/src/components/global/MkMisskeyFlavoredMarkdown.stories.impl.ts
+++ b/packages/frontend/src/components/global/MkMisskeyFlavoredMarkdown.stories.impl.ts
@@ -7,7 +7,7 @@
 import { StoryObj } from '@storybook/vue3';
 import { within } from '@storybook/testing-library';
 import { expect } from '@storybook/jest';
-import MkMisskeyFlavoredMarkdown from './MkMisskeyFlavoredMarkdown.ts';
+import MkMisskeyFlavoredMarkdown from './MkMisskeyFlavoredMarkdown.js';
 export const Default = {
 	render(args) {
 		return {
diff --git a/packages/frontend/src/components/global/MkStickyContainer.vue b/packages/frontend/src/components/global/MkStickyContainer.vue
index 1d707af2d1..70cc68b14c 100644
--- a/packages/frontend/src/components/global/MkStickyContainer.vue
+++ b/packages/frontend/src/components/global/MkStickyContainer.vue
@@ -20,7 +20,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 <script lang="ts" setup>
 import { onMounted, onUnmounted, provide, inject, Ref, ref, watch, shallowRef } from 'vue';
 
-import { CURRENT_STICKY_BOTTOM, CURRENT_STICKY_TOP } from '@/const';
+import { CURRENT_STICKY_BOTTOM, CURRENT_STICKY_TOP } from '@/const.js';
 
 const rootEl = shallowRef<HTMLElement>();
 const headerEl = shallowRef<HTMLElement>();
diff --git a/packages/frontend/src/components/global/MkUrl.stories.impl.ts b/packages/frontend/src/components/global/MkUrl.stories.impl.ts
index 84ac13f95a..b35b6114fd 100644
--- a/packages/frontend/src/components/global/MkUrl.stories.impl.ts
+++ b/packages/frontend/src/components/global/MkUrl.stories.impl.ts
@@ -8,7 +8,7 @@ import { expect } from '@storybook/jest';
 import { userEvent, waitFor, within } from '@storybook/testing-library';
 import { StoryObj } from '@storybook/vue3';
 import { rest } from 'msw';
-import { commonHandlers } from '../../../.storybook/mocks';
+import { commonHandlers } from '../../../.storybook/mocks.js';
 import MkUrl from './MkUrl.vue';
 export const Default = {
 	render(args) {
diff --git a/packages/frontend/src/components/global/MkUserName.stories.impl.ts b/packages/frontend/src/components/global/MkUserName.stories.impl.ts
index 01455e492d..8f47a6c1ab 100644
--- a/packages/frontend/src/components/global/MkUserName.stories.impl.ts
+++ b/packages/frontend/src/components/global/MkUserName.stories.impl.ts
@@ -6,7 +6,7 @@
 /* eslint-disable @typescript-eslint/explicit-function-return-type */
 import { expect } from '@storybook/jest';
 import { StoryObj } from '@storybook/vue3';
-import { userDetailed } from '../../../.storybook/fakes';
+import { userDetailed } from '../../../.storybook/fakes.js';
 import MkUserName from './MkUserName.vue';
 export const Default = {
 	render(args) {
diff --git a/packages/frontend/src/components/global/RouterView.vue b/packages/frontend/src/components/global/RouterView.vue
index 9da8f8c379..99ed8adbef 100644
--- a/packages/frontend/src/components/global/RouterView.vue
+++ b/packages/frontend/src/components/global/RouterView.vue
@@ -17,7 +17,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 
 <script lang="ts" setup>
 import { inject, onBeforeUnmount, provide, shallowRef, ref } from 'vue';
-import { Resolved, Router } from '@/nirax';
+import { Resolved, Router } from '@/nirax.js';
 import { defaultStore } from '@/store.js';
 
 const props = defineProps<{
diff --git a/packages/frontend/src/components/page/page.block.vue b/packages/frontend/src/components/page/page.block.vue
index c039a1c7b7..7dbbaa03b4 100644
--- a/packages/frontend/src/components/page/page.block.vue
+++ b/packages/frontend/src/components/page/page.block.vue
@@ -14,7 +14,7 @@ import XText from './page.text.vue';
 import XSection from './page.section.vue';
 import XImage from './page.image.vue';
 import XNote from './page.note.vue';
-import { Block } from './block.type';
+import { Block } from './block.type.js';
 
 function getComponent(type: string) {
 	switch (type) {
diff --git a/packages/frontend/src/components/page/page.image.vue b/packages/frontend/src/components/page/page.image.vue
index 80a75f02a5..29aebf63e5 100644
--- a/packages/frontend/src/components/page/page.image.vue
+++ b/packages/frontend/src/components/page/page.image.vue
@@ -16,7 +16,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 <script lang="ts" setup>
 import { ref } from 'vue';
 import * as Misskey from 'misskey-js';
-import { ImageBlock } from './block.type';
+import { ImageBlock } from './block.type.js';
 import MediaImage from '@/components/MkMediaImage.vue';
 
 const props = defineProps<{
diff --git a/packages/frontend/src/components/page/page.note.vue b/packages/frontend/src/components/page/page.note.vue
index d052ce2c1f..5ca707dbc2 100644
--- a/packages/frontend/src/components/page/page.note.vue
+++ b/packages/frontend/src/components/page/page.note.vue
@@ -13,7 +13,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 <script lang="ts" setup>
 import { onMounted, Ref, ref } from 'vue';
 import * as Misskey from 'misskey-js';
-import { NoteBlock } from './block.type';
+import { NoteBlock } from './block.type.js';
 import MkNote from '@/components/MkNote.vue';
 import MkNoteDetailed from '@/components/MkNoteDetailed.vue';
 import * as os from '@/os.js';
diff --git a/packages/frontend/src/components/page/page.section.vue b/packages/frontend/src/components/page/page.section.vue
index 84d0399cf8..e4e5a43b59 100644
--- a/packages/frontend/src/components/page/page.section.vue
+++ b/packages/frontend/src/components/page/page.section.vue
@@ -25,7 +25,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 <script lang="ts" setup>
 import { defineAsyncComponent } from 'vue';
 import * as Misskey from 'misskey-js';
-import { SectionBlock } from './block.type';
+import { SectionBlock } from './block.type.js';
 
 const XBlock = defineAsyncComponent(() => import('./page.block.vue'));
 
diff --git a/packages/frontend/src/components/page/page.text.vue b/packages/frontend/src/components/page/page.text.vue
index 1ab2c0f3c3..ee6b2dca5b 100644
--- a/packages/frontend/src/components/page/page.text.vue
+++ b/packages/frontend/src/components/page/page.text.vue
@@ -14,7 +14,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 import { defineAsyncComponent } from 'vue';
 import * as mfm from 'mfm-js';
 import * as Misskey from 'misskey-js';
-import { TextBlock } from './block.type';
+import { TextBlock } from './block.type.js';
 import { extractUrlFromMfm } from '@/scripts/extract-url-from-mfm.js';
 
 const MkUrlPreview = defineAsyncComponent(() => import('@/components/MkUrlPreview.vue'));
diff --git a/packages/frontend/src/directives/hotkey.ts b/packages/frontend/src/directives/hotkey.ts
index 85f06c098d..13e548299f 100644
--- a/packages/frontend/src/directives/hotkey.ts
+++ b/packages/frontend/src/directives/hotkey.ts
@@ -4,7 +4,7 @@
  */
 
 import { Directive } from 'vue';
-import { makeHotkey } from '../scripts/hotkey';
+import { makeHotkey } from '../scripts/hotkey.js';
 
 export default {
 	mounted(el, binding) {
diff --git a/packages/frontend/src/directives/index.ts b/packages/frontend/src/directives/index.ts
index fad6960948..fcd7c3091e 100644
--- a/packages/frontend/src/directives/index.ts
+++ b/packages/frontend/src/directives/index.ts
@@ -5,17 +5,17 @@
 
 import { App } from 'vue';
 
-import userPreview from './user-preview';
-import getSize from './get-size';
-import ripple from './ripple';
-import tooltip from './tooltip';
-import hotkey from './hotkey';
-import appear from './appear';
-import anim from './anim';
-import clickAnime from './click-anime';
-import panel from './panel';
-import adaptiveBorder from './adaptive-border';
-import adaptiveBg from './adaptive-bg';
+import userPreview from './user-preview.js';
+import getSize from './get-size.js';
+import ripple from './ripple.js';
+import tooltip from './tooltip.js';
+import hotkey from './hotkey.js';
+import appear from './appear.js';
+import anim from './anim.js';
+import clickAnime from './click-anime.js';
+import panel from './panel.js';
+import adaptiveBorder from './adaptive-border.js';
+import adaptiveBg from './adaptive-bg.js';
 
 export default function(app: App) {
 	for (const [key, value] of Object.entries(directives)) {
diff --git a/packages/frontend/src/pages/admin/_header_.vue b/packages/frontend/src/pages/admin/_header_.vue
index 03f28b5219..50aa7846e4 100644
--- a/packages/frontend/src/pages/admin/_header_.vue
+++ b/packages/frontend/src/pages/admin/_header_.vue
@@ -38,7 +38,7 @@ import tinycolor from 'tinycolor2';
 import { popupMenu } from '@/os.js';
 import { scrollToTop } from '@/scripts/scroll.js';
 import MkButton from '@/components/MkButton.vue';
-import { globalEvents } from '@/events';
+import { globalEvents } from '@/events.js';
 import { injectPageMetadata } from '@/scripts/page-metadata.js';
 
 type Tab = {
diff --git a/packages/frontend/src/pages/admin/roles.edit.vue b/packages/frontend/src/pages/admin/roles.edit.vue
index 16db8403ed..f9f1eb0a3c 100644
--- a/packages/frontend/src/pages/admin/roles.edit.vue
+++ b/packages/frontend/src/pages/admin/roles.edit.vue
@@ -31,7 +31,7 @@ import { i18n } from '@/i18n.js';
 import { definePageMetadata } from '@/scripts/page-metadata.js';
 import { useRouter } from '@/router.js';
 import MkButton from '@/components/MkButton.vue';
-import { rolesCache } from '@/cache';
+import { rolesCache } from '@/cache.js';
 
 const router = useRouter();
 
diff --git a/packages/frontend/src/pages/admin/roles.vue b/packages/frontend/src/pages/admin/roles.vue
index 1bb91a0a5b..3962e04218 100644
--- a/packages/frontend/src/pages/admin/roles.vue
+++ b/packages/frontend/src/pages/admin/roles.vue
@@ -238,7 +238,7 @@ import { definePageMetadata } from '@/scripts/page-metadata.js';
 import { instance } from '@/instance.js';
 import { useRouter } from '@/router.js';
 import MkFoldableSection from '@/components/MkFoldableSection.vue';
-import { ROLE_POLICIES } from '@/const';
+import { ROLE_POLICIES } from '@/const.js';
 
 const router = useRouter();
 const baseRoleQ = ref('');
diff --git a/packages/frontend/src/pages/clip.vue b/packages/frontend/src/pages/clip.vue
index 3c94db82d7..ec9876f70c 100644
--- a/packages/frontend/src/pages/clip.vue
+++ b/packages/frontend/src/pages/clip.vue
@@ -35,7 +35,7 @@ import * as os from '@/os.js';
 import { definePageMetadata } from '@/scripts/page-metadata.js';
 import { url } from '@/config.js';
 import MkButton from '@/components/MkButton.vue';
-import { clipsCache } from '@/cache';
+import { clipsCache } from '@/cache.js';
 import { isSupportShare } from '@/scripts/navigator.js';
 import copyToClipboard from '@/scripts/copy-to-clipboard.js';
 
diff --git a/packages/frontend/src/pages/my-antennas/edit.vue b/packages/frontend/src/pages/my-antennas/edit.vue
index 896e61f289..c4a62e024b 100644
--- a/packages/frontend/src/pages/my-antennas/edit.vue
+++ b/packages/frontend/src/pages/my-antennas/edit.vue
@@ -16,7 +16,7 @@ import * as os from '@/os.js';
 import { i18n } from '@/i18n.js';
 import { useRouter } from '@/router.js';
 import { definePageMetadata } from '@/scripts/page-metadata.js';
-import { antennasCache } from '@/cache';
+import { antennasCache } from '@/cache.js';
 
 const router = useRouter();
 
diff --git a/packages/frontend/src/pages/my-antennas/index.vue b/packages/frontend/src/pages/my-antennas/index.vue
index 4b2a3b548d..f2bf9a7ec5 100644
--- a/packages/frontend/src/pages/my-antennas/index.vue
+++ b/packages/frontend/src/pages/my-antennas/index.vue
@@ -32,7 +32,7 @@ import { onActivated, computed } from 'vue';
 import MkButton from '@/components/MkButton.vue';
 import { i18n } from '@/i18n.js';
 import { definePageMetadata } from '@/scripts/page-metadata.js';
-import { antennasCache } from '@/cache';
+import { antennasCache } from '@/cache.js';
 import { infoImageUrl } from '@/instance.js';
 
 const antennas = computed(() => antennasCache.value.value ?? []);
diff --git a/packages/frontend/src/pages/my-clips/index.vue b/packages/frontend/src/pages/my-clips/index.vue
index 85c016187d..daa63d0085 100644
--- a/packages/frontend/src/pages/my-clips/index.vue
+++ b/packages/frontend/src/pages/my-clips/index.vue
@@ -33,7 +33,7 @@ import MkClipPreview from '@/components/MkClipPreview.vue';
 import * as os from '@/os.js';
 import { i18n } from '@/i18n.js';
 import { definePageMetadata } from '@/scripts/page-metadata.js';
-import { clipsCache } from '@/cache';
+import { clipsCache } from '@/cache.js';
 
 const pagination = {
 	endpoint: 'clips/list' as const,
diff --git a/packages/frontend/src/pages/my-lists/index.vue b/packages/frontend/src/pages/my-lists/index.vue
index ff360fccfe..0abfb15d98 100644
--- a/packages/frontend/src/pages/my-lists/index.vue
+++ b/packages/frontend/src/pages/my-lists/index.vue
@@ -35,7 +35,7 @@ import MkAvatars from '@/components/MkAvatars.vue';
 import * as os from '@/os.js';
 import { i18n } from '@/i18n.js';
 import { definePageMetadata } from '@/scripts/page-metadata.js';
-import { userListsCache } from '@/cache';
+import { userListsCache } from '@/cache.js';
 import { infoImageUrl } from '@/instance.js';
 import { $i } from '@/account.js';
 
diff --git a/packages/frontend/src/pages/settings/navbar.vue b/packages/frontend/src/pages/settings/navbar.vue
index 5fe7209a0a..0e56ebd844 100644
--- a/packages/frontend/src/pages/settings/navbar.vue
+++ b/packages/frontend/src/pages/settings/navbar.vue
@@ -52,7 +52,7 @@ import MkButton from '@/components/MkButton.vue';
 import FormSlot from '@/components/form/slot.vue';
 import MkContainer from '@/components/MkContainer.vue';
 import * as os from '@/os.js';
-import { navbarItemDef } from '@/navbar';
+import { navbarItemDef } from '@/navbar.js';
 import { defaultStore } from '@/store.js';
 import { unisonReload } from '@/scripts/unison-reload.js';
 import { i18n } from '@/i18n.js';
diff --git a/packages/frontend/src/pages/settings/theme.manage.vue b/packages/frontend/src/pages/settings/theme.manage.vue
index 2a2dd5e764..2c53eaf130 100644
--- a/packages/frontend/src/pages/settings/theme.manage.vue
+++ b/packages/frontend/src/pages/settings/theme.manage.vue
@@ -40,7 +40,7 @@ import MkButton from '@/components/MkButton.vue';
 import { Theme, getBuiltinThemesRef } from '@/scripts/theme.js';
 import copyToClipboard from '@/scripts/copy-to-clipboard.js';
 import * as os from '@/os.js';
-import { getThemes, removeTheme } from '@/theme-store';
+import { getThemes, removeTheme } from '@/theme-store.js';
 import { i18n } from '@/i18n.js';
 import { definePageMetadata } from '@/scripts/page-metadata.js';
 
diff --git a/packages/frontend/src/pages/settings/theme.vue b/packages/frontend/src/pages/settings/theme.vue
index ad2fc6efe9..dedac10270 100644
--- a/packages/frontend/src/pages/settings/theme.vue
+++ b/packages/frontend/src/pages/settings/theme.vue
@@ -85,7 +85,7 @@ import { ColdDeviceStorage, defaultStore } from '@/store.js';
 import { i18n } from '@/i18n.js';
 import { instance } from '@/instance.js';
 import { uniqueBy } from '@/scripts/array.js';
-import { fetchThemes, getThemes } from '@/theme-store';
+import { fetchThemes, getThemes } from '@/theme-store.js';
 import { definePageMetadata } from '@/scripts/page-metadata.js';
 import { miLocalStorage } from '@/local-storage.js';
 
diff --git a/packages/frontend/src/pages/theme-editor.vue b/packages/frontend/src/pages/theme-editor.vue
index eee3e49db1..e14bd6d89b 100644
--- a/packages/frontend/src/pages/theme-editor.vue
+++ b/packages/frontend/src/pages/theme-editor.vue
@@ -91,7 +91,7 @@ import darkTheme from '@/themes/_dark.json5';
 import { host } from '@/config.js';
 import * as os from '@/os.js';
 import { ColdDeviceStorage, defaultStore } from '@/store.js';
-import { addTheme } from '@/theme-store';
+import { addTheme } from '@/theme-store.js';
 import { i18n } from '@/i18n.js';
 import { useLeaveGuard } from '@/scripts/use-leave-guard.js';
 import { definePageMetadata } from '@/scripts/page-metadata.js';
diff --git a/packages/frontend/src/pages/user/home.stories.impl.ts b/packages/frontend/src/pages/user/home.stories.impl.ts
index 80b4f1a9e9..a2ef5d50d1 100644
--- a/packages/frontend/src/pages/user/home.stories.impl.ts
+++ b/packages/frontend/src/pages/user/home.stories.impl.ts
@@ -6,8 +6,8 @@
 /* eslint-disable @typescript-eslint/explicit-function-return-type */
 import { StoryObj } from '@storybook/vue3';
 import { rest } from 'msw';
-import { userDetailed } from '../../../.storybook/fakes';
-import { commonHandlers } from '../../../.storybook/mocks';
+import { userDetailed } from '../../../.storybook/fakes.js';
+import { commonHandlers } from '../../../.storybook/mocks.js';
 import home_ from './home.vue';
 export const Default = {
 	render(args) {
diff --git a/packages/frontend/src/scripts/upload/compress-config.ts b/packages/frontend/src/scripts/upload/compress-config.ts
index 8fe64c8b76..2deb9cbb81 100644
--- a/packages/frontend/src/scripts/upload/compress-config.ts
+++ b/packages/frontend/src/scripts/upload/compress-config.ts
@@ -4,7 +4,7 @@
  */
 
 import isAnimated from 'is-file-animated';
-import { isWebpSupported } from './isWebpSupported';
+import { isWebpSupported } from './isWebpSupported.js';
 import type { BrowserImageResizerConfig } from 'browser-image-resizer';
 
 const compressTypeMap = {
diff --git a/packages/frontend/src/ui/_common_/common.vue b/packages/frontend/src/ui/_common_/common.vue
index 6b69e1accf..6ece7d86d7 100644
--- a/packages/frontend/src/ui/_common_/common.vue
+++ b/packages/frontend/src/ui/_common_/common.vue
@@ -47,7 +47,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 <script lang="ts" setup>
 import { defineAsyncComponent, ref } from 'vue';
 import * as Misskey from 'misskey-js';
-import { swInject } from './sw-inject';
+import { swInject } from './sw-inject.js';
 import XNotification from './notification.vue';
 import { popups, pendingApiRequestsCount } from '@/os.js';
 import { uploads } from '@/scripts/upload.js';
@@ -56,7 +56,7 @@ import { $i } from '@/account.js';
 import { useStream } from '@/stream.js';
 import { i18n } from '@/i18n.js';
 import { defaultStore } from '@/store.js';
-import { globalEvents } from '@/events';
+import { globalEvents } from '@/events.js';
 
 const XStreamIndicator = defineAsyncComponent(() => import('./stream-indicator.vue'));
 const XUpload = defineAsyncComponent(() => import('./upload.vue'));
diff --git a/packages/frontend/src/ui/_common_/navbar-for-mobile.vue b/packages/frontend/src/ui/_common_/navbar-for-mobile.vue
index 17e95c4cc9..7aee7bbc32 100644
--- a/packages/frontend/src/ui/_common_/navbar-for-mobile.vue
+++ b/packages/frontend/src/ui/_common_/navbar-for-mobile.vue
@@ -50,9 +50,9 @@ SPDX-License-Identifier: AGPL-3.0-only
 
 <script lang="ts" setup>
 import { computed, defineAsyncComponent, toRef } from 'vue';
-import { openInstanceMenu } from './common';
+import { openInstanceMenu } from './common.js';
 import * as os from '@/os.js';
-import { navbarItemDef } from '@/navbar';
+import { navbarItemDef } from '@/navbar.js';
 import { $i, openAccountMenu as openAccountMenu_ } from '@/account.js';
 import { defaultStore } from '@/store.js';
 import { i18n } from '@/i18n.js';
diff --git a/packages/frontend/src/ui/classic.header.vue b/packages/frontend/src/ui/classic.header.vue
index aa9f908cec..2060838f5d 100644
--- a/packages/frontend/src/ui/classic.header.vue
+++ b/packages/frontend/src/ui/classic.header.vue
@@ -48,9 +48,9 @@ SPDX-License-Identifier: AGPL-3.0-only
 
 <script lang="ts" setup>
 import { computed, defineAsyncComponent, onMounted, ref } from 'vue';
-import { openInstanceMenu } from './_common_/common';
+import { openInstanceMenu } from './_common_/common.js';
 import * as os from '@/os.js';
-import { navbarItemDef } from '@/navbar';
+import { navbarItemDef } from '@/navbar.js';
 import { openAccountMenu as openAccountMenu_, $i } from '@/account.js';
 import MkButton from '@/components/MkButton.vue';
 import { defaultStore } from '@/store.js';
diff --git a/packages/frontend/src/ui/deck/column.vue b/packages/frontend/src/ui/deck/column.vue
index f5463d6921..9cb0bb2d43 100644
--- a/packages/frontend/src/ui/deck/column.vue
+++ b/packages/frontend/src/ui/deck/column.vue
@@ -43,7 +43,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 
 <script lang="ts" setup>
 import { onBeforeUnmount, onMounted, provide, watch, shallowRef, ref, computed } from 'vue';
-import { updateColumn, swapLeftColumn, swapRightColumn, swapUpColumn, swapDownColumn, stackLeftColumn, popRightColumn, removeColumn, swapColumn, Column } from './deck-store';
+import { updateColumn, swapLeftColumn, swapRightColumn, swapUpColumn, swapDownColumn, stackLeftColumn, popRightColumn, removeColumn, swapColumn, Column } from './deck-store.js';
 import * as os from '@/os.js';
 import { i18n } from '@/i18n.js';
 import { MenuItem } from '@/types/menu.js';
diff --git a/packages/frontend/src/ui/deck/list-column.vue b/packages/frontend/src/ui/deck/list-column.vue
index 854c8d453b..7166561c7a 100644
--- a/packages/frontend/src/ui/deck/list-column.vue
+++ b/packages/frontend/src/ui/deck/list-column.vue
@@ -16,7 +16,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 <script lang="ts" setup>
 import { watch, shallowRef, ref } from 'vue';
 import XColumn from './column.vue';
-import { updateColumn, Column } from './deck-store';
+import { updateColumn, Column } from './deck-store.js';
 import MkTimeline from '@/components/MkTimeline.vue';
 import * as os from '@/os.js';
 import { i18n } from '@/i18n.js';
diff --git a/packages/frontend/src/ui/deck/main-column.vue b/packages/frontend/src/ui/deck/main-column.vue
index 0c52957ec4..c2b8f19079 100644
--- a/packages/frontend/src/ui/deck/main-column.vue
+++ b/packages/frontend/src/ui/deck/main-column.vue
@@ -26,7 +26,7 @@ import * as os from '@/os.js';
 import { i18n } from '@/i18n.js';
 import { mainRouter } from '@/router.js';
 import { PageMetadata, provideMetadataReceiver } from '@/scripts/page-metadata.js';
-import { useScrollPositionManager } from '@/nirax';
+import { useScrollPositionManager } from '@/nirax.js';
 import { getScrollContainer } from '@/scripts/scroll.js';
 
 defineProps<{
diff --git a/packages/frontend/src/widgets/server-metric/index.vue b/packages/frontend/src/widgets/server-metric/index.vue
index f070dbbbe1..1cba51b714 100644
--- a/packages/frontend/src/widgets/server-metric/index.vue
+++ b/packages/frontend/src/widgets/server-metric/index.vue
@@ -21,7 +21,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 
 <script lang="ts" setup>
 import { onUnmounted, ref } from 'vue';
-import { useWidgetPropsManager, Widget, WidgetComponentExpose } from '../widget';
+import { useWidgetPropsManager, Widget, WidgetComponentExpose } from '../widget.js';
 import XCpuMemory from './cpu-mem.vue';
 import XNet from './net.vue';
 import XCpu from './cpu.vue';
diff --git a/packages/frontend/test/init.ts b/packages/frontend/test/init.ts
index dfc02378d5..6d93ff8cb0 100644
--- a/packages/frontend/test/init.ts
+++ b/packages/frontend/test/init.ts
@@ -10,7 +10,7 @@ const fetchMocker = createFetchMock(vi);
 fetchMocker.enableMocks();
 
 // Set i18n
-import locales from '../../../locales';
+import locales from '../../../locales/index.js';
 import { updateI18n } from '@/i18n.js';
 updateI18n(locales['en-US']);
 
@@ -28,7 +28,7 @@ vi.mock('@/store.js', () => {
 					media: false,
 					avatar: false,
 					urlPreview: false,
-					code: false,		
+					code: false,
 				},
 
 			},
diff --git a/packages/frontend/vite.config.local-dev.ts b/packages/frontend/vite.config.local-dev.ts
index aea46f4231..5a6f511c66 100644
--- a/packages/frontend/vite.config.local-dev.ts
+++ b/packages/frontend/vite.config.local-dev.ts
@@ -1,6 +1,6 @@
 import dns from 'dns';
 import { defineConfig } from 'vite';
-import locales from '../../locales';
+import locales from '../../locales/index.js';
 import { getConfig } from './vite.config.js';
 
 dns.setDefaultResultOrder('ipv4first');
diff --git a/packages/frontend/vite.config.ts b/packages/frontend/vite.config.ts
index 8ff3eb1562..98fe0043c1 100644
--- a/packages/frontend/vite.config.ts
+++ b/packages/frontend/vite.config.ts
@@ -3,10 +3,10 @@ import pluginReplace from '@rollup/plugin-replace';
 import pluginVue from '@vitejs/plugin-vue';
 import { type UserConfig, defineConfig } from 'vite';
 
-import locales from '../../locales';
+import locales from '../../locales/index.js';
 import meta from '../../package.json';
-import pluginUnwindCssModuleClassName from './lib/rollup-plugin-unwind-css-module-class-name';
-import pluginJson5 from './vite.json5';
+import pluginUnwindCssModuleClassName from './lib/rollup-plugin-unwind-css-module-class-name.js';
+import pluginJson5 from './vite.json5.js';
 
 const extensions = ['.ts', '.tsx', '.js', '.jsx', '.mjs', '.json', '.json5', '.svg', '.sass', '.scss', '.css', '.vue'];
 
@@ -26,6 +26,7 @@ const hash = (str: string, seed = 0): number => {
 };
 
 const BASE62_DIGITS = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
+
 function toBase62(n: number): string {
 	if (n === 0) {
 		return '0';