Merge pull request #1274 from tf3/partial-type-helper-add-skip-null-o…

…ption

feat(mapped-types): add skip null properties option to partial type

lib/index.ts

@@ -5,6 +5,7 @@ export * from './partial-type.helper';
 export * from './pick-type.helper';
 export {
   applyIsOptionalDecorator,
+  applyValidateIfDefinedDecorator,
   inheritPropertyInitializers,
   inheritTransformationMetadata,
   inheritValidationMetadata,

lib/partial-type.helper.ts

@@ -2,13 +2,27 @@ import { Type } from '@nestjs/common';
 import { MappedType } from './mapped-type.interface';
 import {
   applyIsOptionalDecorator,
+  applyValidateIfDefinedDecorator,
   inheritPropertyInitializers,
   inheritTransformationMetadata,
   inheritValidationMetadata,
 } from './type-helpers.utils';
 import { RemoveFieldsWithType } from './types/remove-fields-with-type.type';
 
-export function PartialType<T>(classRef: Type<T>) {
+export function PartialType<T>(
+  classRef: Type<T>,
+  /**
+   *  Configuration options.
+   */
+  options: {
+    /**
+     * If true, validations will be ignored on a property if it is either null or undefined. If
+     * false, validations will be ignored only if the property is undefined.
+     * @default true
+     */
+    skipNullProperties?: boolean;
+  } = {},
+) {
   abstract class PartialClassType {
     constructor() {
       inheritPropertyInitializers(this, classRef);
@@ -20,7 +34,9 @@ export function PartialType<T>(classRef: Type<T>) {
 
   if (propertyKeys) {
     propertyKeys.forEach((key) => {
-      applyIsOptionalDecorator(PartialClassType, key);
+      options.skipNullProperties === false
+        ? applyValidateIfDefinedDecorator(PartialClassType, key)
+        : applyIsOptionalDecorator(PartialClassType, key);
     });
   }
 

lib/type-helpers.utils.ts

@@ -15,6 +15,20 @@ export function applyIsOptionalDecorator(
   decoratorFactory(targetClass.prototype, propertyKey);
 }
 
+export function applyValidateIfDefinedDecorator(
+  targetClass: Function,
+  propertyKey: string,
+) {
+  if (!isClassValidatorAvailable()) {
+    return;
+  }
+  const classValidator: typeof import('class-validator') = require('class-validator');
+  const decoratorFactory = classValidator.ValidateIf(
+    (_, value) => value !== undefined,
+  );
+  decoratorFactory(targetClass.prototype, propertyKey);
+}
+
 export function inheritValidationMetadata(
   parentClass: Type<any>,
   targetClass: Function,

tests/partial-type.helper.spec.ts

@@ -81,4 +81,44 @@ describe('PartialType', () => {
       expect(updateUserDto.login).toEqual('defaultLogin');
     });
   });
+
+  describe('Configuration options', () => {
+    it('should not ignore validations for null properties when `skipNullProperties` is false', async () => {
+      class UpdateUserDtoDisallowNull extends PartialType(CreateUserDto, {
+        skipNullProperties: false,
+      }) {}
+
+      const updateDto = new UpdateUserDtoDisallowNull();
+      updateDto.password = null as any;
+
+      const validationErrors = await validate(updateDto);
+
+      expect(validationErrors.length).toBe(1);
+      expect(validationErrors[0].constraints).toEqual({
+        isString: 'password must be a string',
+      });
+    });
+
+    it('should ignore validations on null properties when `skipNullProperties` is undefined', async () => {
+      const updateDto = new UpdateUserDto();
+      updateDto.password = null as any;
+
+      const validationErrors = await validate(updateDto);
+
+      expect(validationErrors.length).toBe(0);
+    });
+
+    it('should ignore validations on null properties when `skipNullProperties` is true', async () => {
+      class UpdateUserDtoAllowNull extends PartialType(CreateUserDto, {
+        skipNullProperties: true,
+      }) {}
+
+      const updateDto = new UpdateUserDtoAllowNull();
+      updateDto.password = null as any;
+
+      const validationErrors = await validate(updateDto);
+
+      expect(validationErrors.length).toBe(0);
+    });
+  });
 });