feat(decorators): IsOptional

Signed-off-by: Lexus Drumgold <[email protected]>

Author: unicornware

src/decorators/__tests__/is-optional.decorator.functional.spec.ts

@@ -0,0 +1,21 @@
+/**
+ * @file Functional Tests - IsOptional
+ * @module sneusers/decorators/tests/functional/IsOptional
+ */
+
+import { IsString, validate } from 'class-validator'
+import TestSubject from '../is-optional.decorator'
+
+describe('functional:decorators/IsOptional', () => {
+  it('should ignore property validators if value is undefined', async () => {
+    // Arrange
+    class TestModel {
+      @IsString()
+      @TestSubject()
+      public readonly $property: string | undefined = undefined
+    }
+
+    // Act + Expect
+    expect(await validate(new TestModel())).to.be.an('array').that.is.empty
+  })
+})

src/decorators/index.ts

@@ -7,4 +7,5 @@
  */
 
 export { default as IsNullable } from './is-nullable.decorator'
+export { default as IsOptional } from './is-optional.decorator'
 export { default as IsTimestamp } from './is-timestamp.decorator'

src/decorators/is-optional.decorator.ts

@@ -0,0 +1,34 @@
+/**
+ * @file Decorators - IsOptional
+ * @module sneusers/decorators/IsOptional
+ */
+
+import { isUndefined, type ObjectUnknown } from '@flex-development/tutils'
+import {
+  getMetadataStorage,
+  ValidationTypes,
+  type ValidationOptions
+} from 'class-validator'
+import { ValidationMetadata } from 'class-validator/esm2015/metadata/ValidationMetadata'
+
+/**
+ * Ignores all validators if a property value is `undefined`.
+ *
+ * @param {ValidationOptions} [options] - Validation options
+ * @return {PropertyDecorator} Property decorator
+ */
+const IsOptional = (options: ValidationOptions = {}): PropertyDecorator => {
+  return function (obj: object, name: string | symbol): void {
+    getMetadataStorage().addValidationMetadata(
+      new ValidationMetadata({
+        constraints: [(obj: ObjectUnknown) => !isUndefined(obj[name])],
+        propertyName: name as string,
+        target: obj.constructor,
+        type: ValidationTypes.CONDITIONAL_VALIDATION,
+        validationOptions: options
+      })
+    )
+  }
+}
+
+export default IsOptional