BC-5102 - use type guards

apps/server/src/modules/board/service/submission-item.service.ts

@@ -1,7 +1,7 @@
 import { ObjectId } from 'bson';
-import { Injectable, NotFoundException } from '@nestjs/common';
+import { Injectable, NotFoundException, UnprocessableEntityException } from '@nestjs/common';
 
-import { EntityId, SubmissionContainerElement, SubmissionItem } from '@shared/domain';
+import { EntityId, isSubmissionContainerElement, SubmissionContainerElement, SubmissionItem } from '@shared/domain';
 import { ValidationError } from '@shared/common';
 
 import { BoardDoRepo } from '../repo';
@@ -42,13 +42,17 @@ export class SubmissionItemService {
 	}
 
 	async update(submissionItem: SubmissionItem, completed: boolean): Promise<void> {
-		const parent = (await this.boardDoRepo.findParentOfId(submissionItem.id)) as SubmissionContainerElement;
+		const submissionContainterElement = await this.boardDoRepo.findParentOfId(submissionItem.id);
+		if (!isSubmissionContainerElement(submissionContainterElement)) {
+			throw new UnprocessableEntityException();
+		}
+
 		const now = new Date();
-		if (parent.dueDate && parent.dueDate < now) {
+		if (submissionContainterElement.dueDate && submissionContainterElement.dueDate < now) {
 			throw new ValidationError('not allowed to save anymore');
 		}
 		submissionItem.completed = completed;
 
-		await this.boardDoRepo.save(submissionItem, parent);
+		await this.boardDoRepo.save(submissionItem, submissionContainterElement);
 	}
 }

apps/server/src/modules/board/uc/element.uc.ts

@@ -1,5 +1,12 @@
 import { forwardRef, HttpException, HttpStatus, Inject, Injectable } from '@nestjs/common';
-import { AnyBoardDo, EntityId, SubmissionContainerElement, SubmissionItem, UserRoleEnum } from '@shared/domain';
+import {
+	AnyBoardDo,
+	EntityId,
+	isSubmissionContainerElement,
+	isSubmissionItem,
+	SubmissionItem,
+	UserRoleEnum,
+} from '@shared/domain';
 import { Logger } from '@src/core/logger';
 import { AuthorizationService } from '@src/modules/authorization';
 import { Action } from '@src/modules/authorization/types/action.enum';
@@ -33,33 +40,35 @@ export class ElementUc {
 		contentElementId: EntityId,
 		completed: boolean
 	): Promise<SubmissionItem> {
-		const submissionContainer = (await this.elementService.findById(contentElementId)) as SubmissionContainerElement;
+		const submissionContainerElement = await this.elementService.findById(contentElementId);
 
-		if (!(submissionContainer instanceof SubmissionContainerElement))
+		if (!isSubmissionContainerElement(submissionContainerElement)) {
 			throw new HttpException(
 				'Cannot create submission-item for non submission-container-element',
 				HttpStatus.UNPROCESSABLE_ENTITY
 			);
+		}
 
-		if (!submissionContainer.children.every((child) => child instanceof SubmissionItem))
+		if (!submissionContainerElement.children.every((child) => isSubmissionItem(child))) {
 			throw new HttpException(
 				'Children of submission-container-element must be of type submission-item',
 				HttpStatus.UNPROCESSABLE_ENTITY
 			);
+		}
 
-		const userSubmissionExists = submissionContainer.children.find(
-			(item) => (item as SubmissionItem).userId === userId
-		);
+		const userSubmissionExists = submissionContainerElement.children
+			.filter(isSubmissionItem)
+			.find((item) => item.userId === userId);
 		if (userSubmissionExists) {
 			throw new HttpException(
 				'User is not allowed to have multiple submission-items per submission-container-element',
 				HttpStatus.NOT_ACCEPTABLE
 			);
 		}
 
-		await this.checkPermission(userId, submissionContainer, Action.read, UserRoleEnum.STUDENT);
+		await this.checkPermission(userId, submissionContainerElement, Action.read, UserRoleEnum.STUDENT);
 
-		const submissionItem = await this.submissionItemService.create(userId, submissionContainer, { completed });
+		const submissionItem = await this.submissionItemService.create(userId, submissionContainerElement, { completed });
 
 		return submissionItem;
 	}

apps/server/src/modules/board/uc/submission-item.uc.spec.ts

@@ -194,29 +194,7 @@ describe(SubmissionItemUc.name, () => {
 			it('should throw HttpException', async () => {
 				const { teacher, fileEl } = setup();
 
-				await expect(uc.findSubmissionItems(teacher.id, fileEl.id)).rejects.toThrow(
-					'Id does not belong to a submission container'
-				);
-			});
-		});
-		describe('when called with invalid submission container children', () => {
-			const setup = () => {
-				const teacher = userFactory.buildWithId();
-				const fileEl = fileElementFactory.build();
-				const submissionContainer = submissionContainerElementFactory.build({
-					children: [fileEl],
-				});
-				elementService.findById.mockResolvedValue(submissionContainer);
-
-				return { teacher, submissionContainer };
-			};
-
-			it('should throw HttpException', async () => {
-				const { teacher, submissionContainer } = setup();
-
-				await expect(uc.findSubmissionItems(teacher.id, submissionContainer.id)).rejects.toThrow(
-					'Children of submission-container-element must be of type submission-item'
-				);
+				await expect(uc.findSubmissionItems(teacher.id, fileEl.id)).rejects.toThrow('Id is not submission container');
 			});
 		});
 	});

apps/server/src/modules/board/uc/submission-item.uc.ts

@@ -2,6 +2,8 @@ import { ForbiddenException, forwardRef, HttpException, HttpStatus, Inject, Inje
 import {
 	AnyBoardDo,
 	EntityId,
+	isSubmissionContainerElement,
+	isSubmissionItem,
 	SubmissionContainerElement,
 	SubmissionItem,
 	UserBoardRoles,
@@ -29,22 +31,20 @@ export class SubmissionItemUc {
 		userId: EntityId,
 		submissionContainerId: EntityId
 	): Promise<{ submissionItems: SubmissionItem[]; users: UserBoardRoles[] }> {
-		const submissionContainer = await this.getSubmissionContainer(submissionContainerId);
-		await this.checkPermission(userId, submissionContainer, Action.read);
+		const submissionContainerElement = await this.elementService.findById(submissionContainerId);
 
-		let submissionItems = submissionContainer.children as SubmissionItem[];
-
-		if (!submissionItems.every((child) => child instanceof SubmissionItem)) {
-			throw new HttpException(
-				'Children of submission-container-element must be of type submission-item',
-				HttpStatus.UNPROCESSABLE_ENTITY
-			);
+		if (!isSubmissionContainerElement(submissionContainerElement)) {
+			throw new HttpException('Id is not submission container', HttpStatus.UNPROCESSABLE_ENTITY);
 		}
 
-		const boardAuthorizable = await this.boardDoAuthorizableService.getBoardAuthorizable(submissionContainer);
+		await this.checkPermission(userId, submissionContainerElement, Action.read);
+
+		let submissionItems = submissionContainerElement.children.filter(isSubmissionItem);
+
+		const boardAuthorizable = await this.boardDoAuthorizableService.getBoardAuthorizable(submissionContainerElement);
 		let users = boardAuthorizable.users.filter((user) => user.userRoleEnum === UserRoleEnum.STUDENT);
 
-		const isAuthorizedStudent = await this.isAuthorizedStudent(userId, submissionContainer);
+		const isAuthorizedStudent = await this.isAuthorizedStudent(userId, submissionContainerElement);
 		if (isAuthorizedStudent) {
 			submissionItems = submissionItems.filter((item) => item.userId === userId);
 			users = [];
@@ -86,18 +86,6 @@ export class SubmissionItemUc {
 		return false;
 	}
 
-	private async getSubmissionContainer(submissionContainerId: EntityId): Promise<SubmissionContainerElement> {
-		const submissionContainer = (await this.elementService.findById(
-			submissionContainerId
-		)) as SubmissionContainerElement;
-
-		if (!(submissionContainer instanceof SubmissionContainerElement)) {
-			throw new HttpException('Id does not belong to a submission container', HttpStatus.UNPROCESSABLE_ENTITY);
-		}
-
-		return submissionContainer;
-	}
-
 	private async checkPermission(
 		userId: EntityId,
 		boardDo: AnyBoardDo,

apps/server/src/shared/domain/domainobject/board/submission-item.do.ts

@@ -38,3 +38,7 @@ export interface SubmissionItemProps extends BoardCompositeProps {
 	completed: boolean;
 	userId: EntityId;
 }
+
+export function isSubmissionItem(reference: unknown): reference is SubmissionItem {
+	return reference instanceof SubmissionItem;
+}