From 1e0fa62b67400609a79290a860c84ffd9c74c0ee Mon Sep 17 00:00:00 2001
From: Chau Tran <nartc7789@gmail.com>
Date: Wed, 6 Apr 2022 22:44:48 -0500
Subject: [PATCH] feat(core): allow preMap and postMap to also be called with
 the Mapping

---
 packages/core/src/lib/core.ts                 | 28 +++++++++++++------
 .../src/lib/default-serializer-options.ts     |  5 +++-
 packages/core/src/lib/types.ts                | 24 ++++++++++++----
 3 files changed, 43 insertions(+), 14 deletions(-)

diff --git a/packages/core/src/lib/core.ts b/packages/core/src/lib/core.ts
index 9d70e95e5..19336b659 100644
--- a/packages/core/src/lib/core.ts
+++ b/packages/core/src/lib/core.ts
@@ -137,7 +137,10 @@ export function createMapper({
                         destinationIdentifier
                     );
 
-                    sourceObject = strategy.preMap(Object.freeze(sourceObject));
+                    sourceObject = strategy.preMap(
+                        Object.freeze(sourceObject),
+                        mapping
+                    );
 
                     const destination = mapReturn(
                         mapping,
@@ -149,7 +152,8 @@ export function createMapper({
                         Object.freeze(sourceObject),
                         // seal destination so that consumers cannot add properties to it
                         // or change the property descriptors. but they can still modify it
-                        Object.seal(destination)
+                        Object.seal(destination),
+                        mapping
                     );
                 };
             }
@@ -209,7 +213,8 @@ export function createMapper({
                     ) {
                         let sourceObject = sourceArray[i];
                         sourceObject = strategy.preMap(
-                            Object.freeze(sourceObject)
+                            Object.freeze(sourceObject),
+                            mapping
                         );
 
                         const destination = mapReturn(
@@ -229,7 +234,8 @@ export function createMapper({
                                 Object.freeze(sourceObject),
                                 // seal destination so that consumers cannot add properties to it
                                 // or change the property descriptors. but they can still modify it
-                                Object.seal(destination)
+                                Object.seal(destination),
+                                mapping
                             ) as TDestination
                         );
                     }
@@ -283,7 +289,10 @@ export function createMapper({
                         destinationIdentifier
                     );
 
-                    sourceObject = strategy.preMap(Object.freeze(sourceObject));
+                    sourceObject = strategy.preMap(
+                        Object.freeze(sourceObject),
+                        mapping
+                    );
 
                     mapMutate(
                         mapping,
@@ -294,7 +303,8 @@ export function createMapper({
 
                     strategy.postMap(
                         Object.freeze(sourceObject),
-                        destinationObject
+                        destinationObject,
+                        mapping
                     );
                 };
             }
@@ -356,7 +366,8 @@ export function createMapper({
                         let sourceObject = sourceArray[i];
 
                         sourceObject = strategy.preMap(
-                            Object.freeze(sourceObject)
+                            Object.freeze(sourceObject),
+                            mapping
                         );
 
                         mapMutate(
@@ -374,7 +385,8 @@ export function createMapper({
 
                         strategy.postMap(
                             Object.freeze(sourceObject),
-                            destinationArray[i]
+                            destinationArray[i],
+                            mapping
                         );
                     }
 
diff --git a/packages/core/src/lib/default-serializer-options.ts b/packages/core/src/lib/default-serializer-options.ts
index bd1b3f02d..aa8d48862 100644
--- a/packages/core/src/lib/default-serializer-options.ts
+++ b/packages/core/src/lib/default-serializer-options.ts
@@ -3,7 +3,10 @@ import type { Dictionary, MappingStrategyInitializerOptions } from './types';
 
 export const defaultSerializerOptions = {
     applyMetadata: defaultApplyMetadata,
-    preMap<TSource extends Dictionary<TSource>>(source: TSource): TSource {
+    preMap<
+        TSource extends Dictionary<TSource>,
+        TDestination extends Dictionary<TDestination>
+    >(source: TSource): TSource {
         return source;
     },
     postMap<
diff --git a/packages/core/src/lib/types.ts b/packages/core/src/lib/types.ts
index 6c2bcb573..9c36eed7e 100644
--- a/packages/core/src/lib/types.ts
+++ b/packages/core/src/lib/types.ts
@@ -1,4 +1,4 @@
-import {
+import type {
     ERROR_HANDLER,
     MAPPINGS,
     METADATA_MAP,
@@ -544,13 +544,20 @@ export interface MappingStrategy<TIdentifier extends MetadataIdentifier> {
     retrieveMetadata(
         ...identifiers: TIdentifier[]
     ): Map<TIdentifier, MetadataList>;
-    preMap<TSource extends Dictionary<TSource>>(source: TSource): TSource;
+    preMap<
+        TSource extends Dictionary<TSource>,
+        TDestination extends Dictionary<TDestination>
+    >(
+        source: TSource,
+        mapping: Mapping<TSource, TDestination>
+    ): TSource;
     postMap<
         TSource extends Dictionary<TSource>,
         TDestination extends Dictionary<TDestination>
     >(
         source: TSource,
-        destination: TDestination
+        destination: TDestination,
+        mapping: Mapping<TSource, TDestination>
     ): TDestination | undefined;
 }
 
@@ -560,12 +567,19 @@ export type MappingStrategyInitializer<TIdentifier extends MetadataIdentifier> =
 export interface MappingStrategyInitializerOptions {
     applyMetadata?: ApplyMetadata;
     destinationConstructor?: DestinationConstructor;
-    preMap?<TSource extends Dictionary<TSource>>(source: TSource): TSource;
+    preMap?<
+        TSource extends Dictionary<TSource>,
+        TDestination extends Dictionary<TDestination>
+    >(
+        source: TSource,
+        mapping: Mapping<TSource, TDestination>
+    ): TSource;
     postMap?<
         TSource extends Dictionary<TSource>,
         TDestination extends Dictionary<TDestination>
     >(
         source: TSource,
-        destination: TDestination
+        destination: TDestination,
+        mapping: Mapping<TSource, TDestination>
     ): TDestination;
 }