Merge pull request #203 from KuchiMercy/issue-#122

Inefficient Data Transfer Objects

Author: LaGodxy

src/auth/dto/auth-response.dto.ts

@@ -1,74 +1,139 @@
 import { ApiProperty, ApiPropertyOptional } from '@nestjs/swagger';
+import { Exclude, Expose, Type } from 'class-transformer';
+import { IsString, IsOptional, IsNumber, IsArray, IsEmail, ValidateNested, ArrayMinSize } from 'class-validator';
 
+@Exclude()
 export class TokenPairDto {
+  @Expose()
   @ApiProperty({
     description: 'JWT access token',
     example: 'eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...',
   })
+  @IsString()
   accessToken: string;
 
+  @Expose()
   @ApiProperty({
     description: 'JWT refresh token',
     example: 'eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...',
   })
+  @IsString()
   refreshToken: string;
 
+  @Expose()
   @ApiProperty({
     description: 'Token expiration time in seconds',
     example: 3600,
   })
+  @IsNumber()
   expiresIn: number;
 
+  @Expose()
   @ApiProperty({
     description: 'Token type',
     example: 'Bearer',
   })
+  @IsString()
   tokenType: string;
+
+  constructor(partial: Partial<TokenPairDto>) {
+    Object.assign(this, partial);
+  }
 }
 
+@Exclude()
 export class AuthUserDto {
+  @Expose()
   @ApiProperty({ example: 'user_abc123' })
+  @IsString()
   id: string;
 
+  @Expose()
   @ApiProperty({ example: '[email protected]' })
+  @IsEmail()
   email: string;
 
+  @Expose()
   @ApiPropertyOptional({ example: 'John' })
+  @IsOptional()
+  @IsString()
   firstName?: string;
 
+  @Expose()
   @ApiPropertyOptional({ example: 'Doe' })
+  @IsOptional()
+  @IsString()
   lastName?: string;
 
+  @Expose()
   @ApiPropertyOptional({ example: '0x742d35Cc6634C0532925a3b844Bc454e4438f44e' })
+  @IsOptional()
+  @IsString()
   walletAddress?: string;
 
+  @Expose()
   @ApiProperty({ example: ['user'] })
+  @IsArray()
+  @ArrayMinSize(1)
+  @IsString({ each: true })
   roles: string[];
+
+  constructor(partial: Partial<AuthUserDto>) {
+    Object.assign(this, partial);
+  }
 }
 
+@Exclude()
 export class LoginResponseDto {
+  @Expose()
   @ApiProperty({ type: AuthUserDto })
+  @ValidateNested()
+  @Type(() => AuthUserDto)
   user: AuthUserDto;
 
+  @Expose()
   @ApiProperty({ type: TokenPairDto })
+  @ValidateNested()
+  @Type(() => TokenPairDto)
   tokens: TokenPairDto;
+
+  constructor(partial: Partial<LoginResponseDto>) {
+    Object.assign(this, partial);
+  }
 }
 
+@Exclude()
 export class RegisterResponseDto {
+  @Expose()
   @ApiProperty({ type: AuthUserDto })
+  @ValidateNested()
+  @Type(() => AuthUserDto)
   user: AuthUserDto;
 
+  @Expose()
   @ApiProperty({
     description: 'Message about email verification',
     example: 'Please check your email to verify your account',
   })
+  @IsString()
   message: string;
+
+  constructor(partial: Partial<RegisterResponseDto>) {
+    Object.assign(this, partial);
+  }
 }
 
+@Exclude()
 export class MessageResponseDto {
+  @Expose()
   @ApiProperty({
     description: 'Response message',
     example: 'Operation completed successfully',
   })
+  @IsString()
   message: string;
+
+  constructor(partial: Partial<MessageResponseDto>) {
+    Object.assign(this, partial);
+  }
 }

src/common/dtos/api-response.dto.ts

@@ -1,43 +1,80 @@
 import { ApiProperty } from '@nestjs/swagger';
+import { Exclude, Expose, Transform, Type } from 'class-transformer';
+import { IsBoolean, IsNumber, IsString, IsOptional, IsArray, ValidateNested, IsObject } from 'class-validator';
+
+/**
+ * Error details structure
+ */
+@Exclude()
+export class ErrorDetailsDto {
+  @Expose()
+  @ApiProperty({ description: 'Error code', example: 'VALIDATION_ERROR' })
+  @IsString()
+  code: string;
+
+  @Expose()
+  @ApiProperty({ description: 'Additional error details', example: ['Field is required'], type: [String] })
+  @IsOptional()
+  @IsArray()
+  @IsString({ each: true })
+  details?: string[];
+
+  constructor(partial: Partial<ErrorDetailsDto>) {
+    Object.assign(this, partial);
+  }
+}
 
 /**
  * Standardized API Response Structure
  * Unified format for all success and error responses
  */
+@Exclude()
 export class ApiResponseDto<T> {
+  @Expose()
   @ApiProperty({ description: 'Indicates if the operation was successful' })
+  @IsBoolean()
   success: boolean;
 
+  @Expose()
   @ApiProperty({ description: 'HTTP status code' })
+  @IsNumber()
   statusCode: number;
 
+  @Expose()
   @ApiProperty({ description: 'Response message' })
+  @IsString()
   message: string;
 
+  @Expose()
   @ApiProperty({ description: 'Response data payload', required: false })
+  @IsOptional()
   data: T | null;
 
+  @Expose()
   @ApiProperty({
     description: 'Error details if success is false',
     required: false,
-    type: 'object',
-    properties: {
-      code: { type: 'string' },
-      details: { type: 'array', items: { type: 'string' } },
-    },
+    type: ErrorDetailsDto,
   })
-  error?: {
-    code: string;
-    details?: string[];
-  };
+  @IsOptional()
+  @ValidateNested()
+  @Type(() => ErrorDetailsDto)
+  error?: ErrorDetailsDto;
 
+  @Expose()
   @ApiProperty({ description: 'UTC timestamp of the response' })
+  @IsString()
+  @Transform(({ value }) => value || new Date().toISOString())
   timestamp: string;
 
+  @Expose()
   @ApiProperty({ description: 'API request path' })
+  @IsString()
   path: string;
 
+  @Expose()
   @ApiProperty({ description: 'Unique request/correlation identifier' })
+  @IsString()
   requestId: string;
 
   constructor(partial: Partial<ApiResponseDto<T>>) {
@@ -48,7 +85,13 @@ export class ApiResponseDto<T> {
   /**
    * Static helper to create a success response
    */
-  static success<T>(data: T, message = 'Success', statusCode = 200, path?: string, requestId?: string): ApiResponseDto<T> {
+  static success<T>(
+    data: T,
+    message = 'Success',
+    statusCode = 200,
+    path?: string,
+    requestId?: string,
+  ): ApiResponseDto<T> {
     return new ApiResponseDto({
       success: true,
       statusCode,
@@ -75,10 +118,10 @@ export class ApiResponseDto<T> {
       statusCode,
       message,
       data: null,
-      error: {
+      error: new ErrorDetailsDto({
         code: errorCode,
         details,
-      },
+      }),
       path,
       requestId,
     });