feat: pass ClassTransformOptions to the transformFn of @Transform (#294)

Author: lucas-gregoire

README.md

@@ -777,12 +777,13 @@ The `@Transform` decorator is given more arguments to let you configure how you
 @Transform(({ value, key, obj, type }) => value)
 ```
 
-| Argument | Description                                   |
-| -------- | --------------------------------------------- |
-| `value`  | The property value before the transformation. |
-| `key`    | The name of the transformed property.         |
-| `obj`    | The transformation source object.             |
-| `type`   | The transformation type.                      |
+| Argument  | Description                                             |
+| --------- | ------------------------------------------------------- |
+| `value`   | The property value before the transformation.           |
+| `key`     | The name of the transformed property.                   |
+| `obj`     | The transformation source object.                       |
+| `type`    | The transformation type.                                |
+| `options` | The options object passed to the transformation method. |
 
 ## Other decorators[⬆](#table-of-contents)
 

src/TransformOperationExecutor.ts

@@ -385,7 +385,7 @@ export class TransformOperationExecutor {
     }
 
     metadatas.forEach(metadata => {
-      value = metadata.transformFn({ value, key, obj, type: transformationType });
+      value = metadata.transformFn({ value, key, obj, type: transformationType, options: this.options });
     });
 
     return value;

src/interfaces/metadata/transform-fn-params.interface.ts

@@ -1,8 +1,10 @@
 import { TransformationType } from '../../enums';
+import { ClassTransformOptions } from '../class-transformer-options.interface';
 
 export interface TransformFnParams {
   value: any;
   key: string;
   obj: any;
   type: TransformationType;
+  options: ClassTransformOptions;
 }

test/functional/custom-transform.spec.ts

@@ -1,6 +1,6 @@
 /* eslint-disable @typescript-eslint/camelcase */
 import 'reflect-metadata';
-import { classToClass, classToPlain, plainToClass, TransformFnParams } from '../../src/index';
+import { classToClass, classToPlain, ClassTransformOptions, plainToClass, TransformFnParams } from '../../src/index';
 import { defaultMetadataStorage } from '../../src/storage';
 import { Expose, Transform, Type } from '../../src/decorators';
 import { TransformationType } from '../../src/enums';
@@ -121,11 +121,13 @@ describe('custom transformation decorator', () => {
     let keyArg: string;
     let objArg: any;
     let typeArg: TransformationType;
+    let optionsArg: ClassTransformOptions;
 
-    function transformCallback({ value, key, obj, type }: TransformFnParams): any {
+    function transformCallback({ value, key, obj, type, options }: TransformFnParams): any {
       keyArg = key;
       objArg = obj;
       typeArg = type;
+      optionsArg = options;
       return value;
     }
 
@@ -138,19 +140,26 @@ describe('custom transformation decorator', () => {
     const plainUser = {
       name: 'Johny Cage',
     };
+    const options: ClassTransformOptions = {
+      groups: ['user', 'user.email'],
+      version: 2,
+    };
 
-    plainToClass(User, plainUser);
+    plainToClass(User, plainUser, options);
     expect(keyArg).toBe('name');
     expect(objArg).toEqual(plainUser);
     expect(typeArg).toEqual(TransformationType.PLAIN_TO_CLASS);
+    expect(optionsArg).toBe(options);
 
     const user = new User();
     user.name = 'Johny Cage';
+    optionsArg = undefined;
 
-    classToPlain(user);
+    classToPlain(user, options);
     expect(keyArg).toBe('name');
     expect(objArg).toEqual(user);
     expect(typeArg).toEqual(TransformationType.CLASS_TO_PLAIN);
+    expect(optionsArg).toBe(options);
   });
 
   let model: any;