[FEAT] Improve error message of isEnum validator

README.md

@@ -20,6 +20,7 @@ A collection of [NestJS](https://docs.nestjs.com) components. This repository is
   - [NestJS Google Cloud PubSub MicroService](#nestjs-google-cloud-pubsub-microservice)
   - [NestJS Google Cloud PubSub Client Proxy](#nestjs-google-cloud-pubsub-client-proxy)
   - [NestJS custom decorators](#nestjs-custom-decorators)
+  - [NestJS class validators](#nestjs-class-validators)
 
 ## NestJS Pagination
 
@@ -57,6 +58,12 @@ A set of custom decorators for NestJS.
 
 See [the documentation here](./packages/custom-decorators).
 
+## NestJS class validators
+
+A package containing overriden class validators.
+
+See [the documentation here](./packages/class-validators).
+
 # Contribution
 
 This repository is managed by [Lerna.js](https://lerna.js.org). If you want to contribute, you need to follow these instructions:

package.json

@@ -94,6 +94,7 @@
     "@algoan/nestjs-google-pubsub-microservice": "file:packages/google-pubsub-microservice",
     "@algoan/nestjs-http-exception-filter": "file:packages/http-exception-filter",
     "@algoan/nestjs-logging-interceptor": "file:packages/logging-interceptor",
-    "@algoan/nestjs-pagination": "file:packages/pagination"
+    "@algoan/nestjs-pagination": "file:packages/pagination",
+    "@algoan/nestjs-class-validators": "file:packages/class-validators"
   }
 }

packages/class-validators/README.md

@@ -0,0 +1,21 @@
+# Nestjs class validators
+
+A set of class validators based on the class-validator package (https://www.npmjs.com/package/@nestjs/class-validator/v/0.13.1).
+
+## Installation
+
+```bash
+npm install --save @algoan/nestjs-class-validators
+```
+
+## IsEnum
+
+A class validator that validates the enum type.
+
+### Usage
+
+```ts
+ @IsEnum(UserType)
+ public userType: UserType;
+```
+

packages/class-validators/package.json

@@ -0,0 +1,14 @@
+{
+  "name": "@algoan/nestjs-class-validators",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "author": "",
+  "license": "ISC",
+  "dependencies": {
+    "class-validator": "^0.14.0"
+  }
+}

packages/class-validators/src/index.ts

@@ -0,0 +1,2 @@
+export { IsEnum } from './is-enum.decorator';
+export * from 'class-validator';

packages/class-validators/src/is-enum.decorator.ts

@@ -0,0 +1,13 @@
+import { IsEnum as OriginalIsEnum, ValidationOptions } from 'class-validator';
+
+/**
+ * Checks if a given value is the member of the provided enum.
+ *
+ * This an override for the class-validator IsEnum validator.
+ * The error message is enhanced with the invalid value
+ */
+export const IsEnum = (entity: object, validationOptions?: ValidationOptions): PropertyDecorator =>
+  OriginalIsEnum(entity, {
+    message: '$property has the value $value but must be one of the following values: $constraint2',
+    ...validationOptions,
+  });

packages/class-validators/test/is-enum-decorator.test.ts

@@ -0,0 +1,79 @@
+import { IsEnum } from '../src/is-enum.decorator';
+import { Validator, ValidatorOptions } from 'class-validator';
+
+function validateValues(
+  object: { testProperty: any },
+  values: any[],
+  validatorOptions?: ValidatorOptions,
+): Promise<any> {
+  const validator = new Validator();
+  const promises = values.map((value) => {
+    object.testProperty = value;
+    return validator.validate(object, validatorOptions).then((errors) => {
+      expect(errors.length).toEqual(0);
+      if (errors.length > 0) {
+        console.log(`Unexpected errors: ${JSON.stringify(errors)}`);
+        throw new Error('Unexpected validation errors');
+      }
+    });
+  });
+
+  return Promise.all(promises);
+}
+
+function checkReturnedError(
+  object: { testProperty: any },
+  values: any[],
+  validationType: string,
+  messages: string[],
+  validatorOptions?: ValidatorOptions,
+): Promise<any> {
+  let messagesIncrementor: number = 0;
+  const validator = new Validator();
+  const promises = values.map((value) => {
+    object.testProperty = value;
+    return validator.validate(object, validatorOptions).then((errors) => {
+      expect(errors.length).toEqual(1);
+      expect(errors[0].target).toEqual(object);
+      expect(errors[0].property).toEqual('testProperty');
+      expect(errors[0].constraints).toEqual({ [validationType]: messages[messagesIncrementor] });
+      expect(errors[0].value).toEqual(value);
+      messagesIncrementor++;
+    });
+  });
+
+  return Promise.all(promises);
+}
+
+describe('Tests related to the custom IsEnum Decorator', () => {
+  enum CustomEnum {
+    FIRST_ITEM = 'first-item',
+    SECOND_ITEM = 'second-item',
+  }
+
+  class TestClass {
+    @IsEnum(CustomEnum)
+    testProperty: CustomEnum = CustomEnum.FIRST_ITEM;
+  }
+
+  it('should validate the correct values', () => {
+    return validateValues(new TestClass(), [
+      CustomEnum.FIRST_ITEM,
+      CustomEnum.SECOND_ITEM,
+      'first-item',
+      'second-item',
+    ]);
+  });
+
+  it('should not validate invalid values and return the correct errors', () => {
+    const validationType = 'isEnum';
+    const firstMessage =
+      'testProperty has the value false-value-1 but must be one of the following values: first-item, second-item';
+    const secondMessage =
+      'testProperty has the value false-value-2 but must be one of the following values: first-item, second-item';
+    return checkReturnedError(new TestClass(), ['false-value-1', 'false-value-2'], validationType, [
+      firstMessage,
+      secondMessage,
+    ]);
+  });
+});