replace all == null (google style) to isNil for clarity

server/src/auth/auth.service.ts

@@ -1,7 +1,8 @@
 import { BadRequestException, Injectable, Logger } from '@nestjs/common';
-import { UserService } from '../user/user.service';
+import { isNil } from 'src/common/utils';
 import User from '../entities/user.entity';
 import { ProviderInfo } from '../types/user';
+import { UserService } from '../user/user.service';
 
 @Injectable()
 export class AuthService {
@@ -23,7 +24,7 @@ export class AuthService {
  const user =
  await this.userService.findUserByProviderInfo(mockProviderInfo);
 
- if (user == null) {
+ if (isNil(user)) {
  this.logger.debug('잘못된 로그인 요청입니다!');
  throw new BadRequestException('잘못된 로그인 요청입니다!');
  }

server/src/common/middleware/session.ts

@@ -1,10 +1,11 @@
 import RedisStore from 'connect-redis';
 import session from 'express-session';
 import Redis from 'ioredis';
+import { isNil } from '../utils';
 
 export const makeRedisStore = () => {
  const REDIS_HOST = process.env.REDIS_HOSTNAME;
- if (REDIS_HOST == null) throw new Error('REDIS_HOST is not defined');
+ if (isNil(REDIS_HOST)) throw new Error('REDIS_HOST is not defined');
 
  const redis = new Redis({
  host: REDIS_HOST,

server/src/problem/problem.service.ts

@@ -1,7 +1,8 @@
 import { Injectable } from '@nestjs/common';
 import { InjectRepository } from '@nestjs/typeorm';
-import Problem from '../entities/problem.entity';
+import { isNil } from 'src/common/utils';
 import { ILike, In, Raw, Repository } from 'typeorm';
+import Problem from '../entities/problem.entity';
 import { RandomProblemDto } from './dto/random.problem.dto';
 import { SearchProblemDto } from './dto/search.problem.dto';
 
@@ -57,7 +58,7 @@ export class ProblemService {
  const problemEntities: Problem[] = [];
  for (const bojProblemId of bojProblemIds) {
  const problem = await this.getProblemByBojProblemId(bojProblemId);
- if (problem == null) {
+ if (isNil(problem)) {
  throw new Error(`bojProblemId ${bojProblemId} not found`);
  }
  problemEntities.push(problem);

server/src/room/room.service.ts

@@ -8,6 +8,7 @@ import {
 } from '@nestjs/common';
 import { InjectRepository } from '@nestjs/typeorm';
 import * as crypto from 'crypto';
+import { isNil } from 'src/common/utils';
 import { SubmissionService } from 'src/submission/submission.service';
 import { Repository } from 'typeorm';
 import Room from '../entities/room.entity';
@@ -43,7 +44,7 @@ export class RoomService {
  throw new BadRequestException('이미 참가한 방이 있습니다.');
  }
 
- if (user.username == null)
+ if (isNil(user.username))
  throw new BadRequestException('username이 없습니다.');
  const code = await this.createRoomCode(user.username);
 
@@ -81,7 +82,7 @@ export class RoomService {
  throw new BadRequestException('존재하지 않는 방입니다.');
  }
  const room = roomUsers[0].room;
- if (room == null) {
+ if (isNil(room)) {
  throw new InternalServerErrorException('방을 찾을 수 없습니다.');
  }
  this.logger.debug(`user ${user.username} joining room ${room.code}...`);
@@ -96,7 +97,7 @@ export class RoomService {
 
  async exitRoom(user: User) {
  const joinedRooms = await user.joinedRooms;
- if (joinedRooms == null) {
+ if (isNil(joinedRooms) || joinedRooms.length === 0) {
  throw new InternalServerErrorException(
  '참가 중인 방을 찾을 수 없습니다.',
  );
@@ -110,14 +111,14 @@ export class RoomService {
  await this.roomUserRepository.remove(roomUser);
 
  const room = roomUser.room;
- if (room == null) {
+ if (isNil(room)) {
  throw new InternalServerErrorException('방을 찾을 수 없습니다.');
  }
 
  await this.socketService.notifyExit(user.username, room);
 
  const numberOfJoinedUsers = (await room.joinedUsers)?.length;
- if (numberOfJoinedUsers == null || numberOfJoinedUsers === 0) {
+ if (isNil(numberOfJoinedUsers) || numberOfJoinedUsers === 0) {
  await this.destroyRoom(room);
  }
  }

server/src/socket/socket.gateway.ts

@@ -1,3 +1,5 @@
+import { Logger, UseFilters } from '@nestjs/common';
+import { InjectRepository } from '@nestjs/typeorm';
 import {
  ConnectedSocket,
  MessageBody,
@@ -9,17 +11,16 @@ import {
  WsException,
 } from '@nestjs/websockets';
 import { Server, Socket } from 'socket.io';
+import { isNil } from 'src/common/utils';
+import { Repository } from 'typeorm';
+import Room from '../entities/room.entity';
+import User from '../entities/user.entity';
+import { ProblemService } from '../problem/problem.service';
 import { ChatEvent, MessageInterface } from '../types/message-interface';
-import { Logger, UseFilters } from '@nestjs/common';
+import { RoomInfoType } from '../types/room-info';
 import { UserService } from '../user/user.service';
-import User from '../entities/user.entity';
 import { WebsocketExceptionsFilter } from './socket.filter';
-import Room from '../entities/room.entity';
-import { RoomInfoType } from '../types/room-info';
 import { SocketService } from './socket.service';
-import { ProblemService } from '../problem/problem.service';
-import { InjectRepository } from '@nestjs/typeorm';
-import { Repository } from 'typeorm';
 
 @WebSocketGateway({
  cors: {
@@ -91,7 +92,7 @@ export class SocketGateway implements OnGatewayConnection, OnGatewayDisconnect {
  provider,
  providerId,
  });
- if (user == null) throw new WsException('user is null');
+ if (isNil(user)) throw new WsException('user is null');
 
  await this.socketService.gameStart(user, roomInfo);
  }
@@ -109,7 +110,7 @@ export class SocketGateway implements OnGatewayConnection, OnGatewayDisconnect {
  message,
  );
 
- if (this.server == null) throw new WsException('server is null');
+ if (isNil(this.server)) throw new WsException('server is null');
 
  this.logger.debug(`--> ws: chat-message ${message.body}`);
  this.server.to(room.code).emit('chat-message', message);
@@ -143,9 +144,9 @@ export class SocketGateway implements OnGatewayConnection, OnGatewayDisconnect {
 
  getUser(client: Socket): User {
  const request = client.request as any;
- if (request == null) throw new WsException('request is null');
+ if (isNil(request)) throw new WsException('request is null');
  const user = request.user;
- if (user == null) throw new WsException('user is null');
+ if (isNil(user)) throw new WsException('user is null');
  return user as User;
  }
 }

server/src/socket/socket.service.ts

@@ -1,16 +1,17 @@
 import { Injectable, Logger } from '@nestjs/common';
-import Room from '../entities/room.entity';
+import { InjectRepository } from '@nestjs/typeorm';
 import { WsException } from '@nestjs/websockets';
-import { RoomInfoType } from '../types/room-info';
 import { Server } from 'socket.io';
+import { isNil } from 'src/common/utils';
+import { Repository } from 'typeorm';
+import * as util from 'util';
 import { Status } from '../const/boj-results';
-import { ChatEvent, MessageInterface } from '../types/message-interface';
-import { ProblemType } from '../types/problem-type';
+import Room from '../entities/room.entity';
 import User from '../entities/user.entity';
-import * as util from 'util';
-import { Repository } from 'typeorm';
-import { InjectRepository } from '@nestjs/typeorm';
 import { ProblemService } from '../problem/problem.service';
+import { ChatEvent, MessageInterface } from '../types/message-interface';
+import { ProblemType } from '../types/problem-type';
+import { RoomInfoType } from '../types/room-info';
 import { UserService } from '../user/user.service';
 
 @Injectable()
@@ -54,10 +55,10 @@ export class SocketService {
  const host = await room.host;
  const problems = await room.problems;
 
- if (roomUsers == null) throw new WsException('roomUsers is null');
- if (host == null) throw new WsException('host is null');
- if (problems == null || problems.length === 0)
- throw new WsException('problems is null');
+ if (isNil(roomUsers)) throw new WsException('roomUsers is null');
+ if (isNil(host)) throw new WsException('host is null');
+ if (isNil(problems) || problems.length === 0)
+ throw new WsException('problems do not exist');
 
  const problemTypes: ProblemType[] = problems.map((problem) => {
  return {
@@ -144,7 +145,7 @@ export class SocketService {
  // check if the user is the host of the room
 
  const host = await roomUser.room.host;
- if (host == null) throw new WsException('host is null');
+ if (isNil(host)) throw new WsException('host is null');
  if (host.id !== user.id) {
  throw new WsException('방장이 아닙니다.');
  }
@@ -154,8 +155,8 @@ export class SocketService {
  // update room entity properties: problems, isStarted, endAt
 
  const { problems, duration } = startingRoomInfo;
- if (problems == null) throw new WsException('problems is null');
- if (duration == null) throw new WsException('duration is null');
+ if (isNil(problems)) throw new WsException('problems is null');
+ if (isNil(duration)) throw new WsException('duration is null');
  const bojProblemIds = problems.map((problem) => problem.bojProblemId);
  const problemEntities =
  await this.problemService.getProblemsByBojProblemIds(bojProblemIds);

server/src/submission/submission.service.ts

@@ -7,6 +7,7 @@ import {
 } from '@nestjs/common';
 import { InjectRepository } from '@nestjs/typeorm';
 import * as cheerio from 'cheerio';
+import { isNil } from 'src/common/utils';
 import Room from 'src/entities/room.entity';
 import { RankingResponseDto } from 'src/room-user/dto/ranking-response.dto';
 import { EntityManager, Repository } from 'typeorm';
@@ -52,7 +53,7 @@ export class SubmissionService {
  if (!user) throw new BadRequestException('존재하지 않는 유저입니다.');
 
  const roomUsers = await user.joinedRooms;
- if (roomUsers == null || roomUsers.length === 0)
+ if (isNil(roomUsers) || roomUsers.length === 0)
  throw new BadRequestException('참여중인 방이 없습니다.');
 
  const roomUser = roomUsers[0];
@@ -64,17 +65,17 @@ export class SubmissionService {
  }
 
  const endAt = room.endAt;
- if (endAt == null || endAt < new Date()) {
+ if (isNil(endAt) || endAt < new Date()) {
  throw new BadRequestException('이미 종료된 방입니다.');
  }
 
  const problems = await room.problems;
- if (problems == null || problems.length === 0)
+ if (isNil(problems) || problems.length === 0)
  throw new BadRequestException('문제가 없는 방입니다.');
 
  const problem =
  await this.problemService.getProblemByBojProblemId(bojProblemId);
- if (problem == null)
+ if (isNil(problem))
  throw new BadRequestException('존재하지 않는 문제입니다.');
 
  if (
@@ -83,7 +84,7 @@ export class SubmissionService {
  throw new BadRequestException('참여중인 방에 없는 문제입니다.');
  }
 
- if (user.username == null)
+ if (isNil(user.username))
  throw new BadRequestException('username이 없습니다.');
 
  await this.socketService.submitCode(

server/src/user/user.service.ts

@@ -4,9 +4,10 @@ import {
  InternalServerErrorException,
 } from '@nestjs/common';
 import { InjectRepository } from '@nestjs/typeorm';
-import { ProviderInfo } from '../types/user';
+import { isNil } from 'src/common/utils';
 import { Repository } from 'typeorm';
 import User from '../entities/user.entity';
+import { ProviderInfo } from '../types/user';
 import { CreateUserDto } from './dto/create.user.dto';
 
 @Injectable()
@@ -48,15 +49,15 @@ export class UserService {
 
  async findJoinedRooms(user: User) {
  const joinedRooms = await user.joinedRooms;
- if (joinedRooms == null) {
+ if (isNil(joinedRooms)) {
  throw new BadRequestException('joinedRooms is null');
  }
  return joinedRooms;
  }
 
  async getSingleJoinedRoom(user: User) {
  const joinedRooms = await user.joinedRooms;
- if (joinedRooms == null) {
+ if (isNil(joinedRooms)) {
  throw new InternalServerErrorException('joinedRooms is null');
  }
  if (joinedRooms.length !== 1) {