Add custom decorator

@match decorator can be used to validate two same property

.gitignore

@@ -166,3 +166,5 @@ lerna-debug.log*
 # API Clients - Thunder Client
 thunder-tests
 thunder-tests/*.json
+thunder-tests/
+/thunder-tests

src/auth/dto/signup.dto.ts

@@ -5,6 +5,7 @@ import {
     IsString,
     IsStrongPassword,
 } from 'class-validator';
+import { Match } from 'src/common/decorators';
 
 export class SignupDto {
     @IsString()
@@ -30,4 +31,13 @@ export class SignupDto {
         example: 'Abcd@1234',
     })
     password: string;
+
+    @IsNotEmpty()
+    @IsStrongPassword()
+    @Match(SignupDto, o => o.password)
+    @ApiProperty({
+        description: 'Confirm password',
+        example: 'Abcd@1234',
+    })
+    confirmPassword: string;
 }

src/common/decorators/index.ts

@@ -1,3 +1,4 @@
 export * from './GetUser.decorator';
 export * from './IsValidMongoId.decorator';
 export * from './apiPaginatedResponse.decorator';
+export * from './match.decorator';

src/common/decorators/match.decorator.ts

@@ -0,0 +1,38 @@
+import { ClassConstructor } from 'class-transformer';
+import {
+    ValidationArguments,
+    ValidationOptions,
+    ValidatorConstraint,
+    ValidatorConstraintInterface,
+    registerDecorator,
+} from 'class-validator';
+
+export const Match = <T>(
+    type: ClassConstructor<T>,
+    property: (o: T) => any,
+    validationOptions?: ValidationOptions,
+) => {
+    return (object: any, propertyName: string) => {
+        registerDecorator({
+            target: object.constructor,
+            propertyName,
+            options: validationOptions,
+            constraints: [property],
+            validator: MatchConstraint,
+        });
+    };
+};
+
+@ValidatorConstraint({ name: 'Match' })
+export class MatchConstraint implements ValidatorConstraintInterface {
+    validate(value: any, args: ValidationArguments) {
+        const [fn] = args.constraints;
+        return fn(args.object) === value;
+    }
+
+    defaultMessage(args: ValidationArguments) {
+        const [constraintProperty]: (() => any)[] = args.constraints;
+        const prop = constraintProperty.toString().split('. ')[1];
+        return `${prop} and ${args.property} does not match`;
+    }
+}