refactor(backend): Array.prototype.filterでの非null確認ではisNotNull関数を使うように (#13442)

* `Array.prototype.filter`での非null確認では`isNotNull`関数を使うように

* `{}` -> `NonNullable<unknown>`

packages/backend/src/core/entities/DriveFileEntityService.ts

@@ -259,7 +259,7 @@ export class DriveFileEntityService {
 		options?: PackOptions,
 	): Promise<Packed<'DriveFile'>[]> {
 		const items = await Promise.all(files.map(f => this.packNullable(f, options)));
-		return items.filter((x): x is Packed<'DriveFile'> => x != null);
+		return items.filter(isNotNull);
 	}
 
 	@bindThis

packages/backend/src/core/entities/PageEntityService.ts

@@ -14,6 +14,7 @@ import type { MiPage } from '@/models/Page.js';
 import type { MiDriveFile } from '@/models/DriveFile.js';
 import { bindThis } from '@/decorators.js';
 import { IdService } from '@/core/IdService.js';
+import { isNotNull } from '@/misc/is-not-null.js';
 import { UserEntityService } from './UserEntityService.js';
 import { DriveFileEntityService } from './DriveFileEntityService.js';
 
@@ -102,7 +103,7 @@ export class PageEntityService {
 			script: page.script,
 			eyeCatchingImageId: page.eyeCatchingImageId,
 			eyeCatchingImage: page.eyeCatchingImageId ? await this.driveFileEntityService.pack(page.eyeCatchingImageId) : null,
-			attachedFiles: this.driveFileEntityService.packMany((await Promise.all(attachedFiles)).filter((x): x is MiDriveFile => x != null)),
+			attachedFiles: this.driveFileEntityService.packMany((await Promise.all(attachedFiles)).filter(isNotNull)),
 			likedCount: page.likedCount,
 			isLiked: meId ? await this.pageLikesRepository.exists({ where: { pageId: page.id, userId: meId } }) : undefined,
 		});

packages/backend/src/core/entities/UserEntityService.ts

@@ -25,6 +25,7 @@ import { IdService } from '@/core/IdService.js';
 import type { AnnouncementService } from '@/core/AnnouncementService.js';
 import type { CustomEmojiService } from '@/core/CustomEmojiService.js';
 import { AvatarDecorationService } from '@/core/AvatarDecorationService.js';
+import { isNotNull } from '@/misc/is-not-null.js';
 import type { OnModuleInit } from '@nestjs/common';
 import type { NoteEntityService } from './NoteEntityService.js';
 import type { DriveFileEntityService } from './DriveFileEntityService.js';
@@ -384,7 +385,7 @@ export class UserEntityService implements OnModuleInit {
 				movedTo: user.movedToUri ? this.apPersonService.resolvePerson(user.movedToUri).then(user => user.id).catch(() => null) : null,
 				alsoKnownAs: user.alsoKnownAs
 					? Promise.all(user.alsoKnownAs.map(uri => this.apPersonService.fetchPerson(uri).then(user => user?.id).catch(() => null)))
-						.then(xs => xs.length === 0 ? null : xs.filter(x => x != null) as string[])
+						.then(xs => xs.length === 0 ? null : xs.filter(isNotNull))
 					: null,
 				createdAt: this.idService.parse(user.id).date.toISOString(),
 				updatedAt: user.updatedAt ? user.updatedAt.toISOString() : null,