From 0340d937c0fae5e1f0dabf429a624a81b1ab4e95 Mon Sep 17 00:00:00 2001
From: kiwi-jang <jh145478@gmail.com>
Date: Mon, 6 Nov 2023 17:48:25 +0900
Subject: [PATCH] refactor: Improve modularity by splitting AutoAspectExecutor

---
 src/auto-aspect-executor.ts | 123 ++++++++++++++++++++----------------
 src/core/types.ts           |   6 ++
 src/create-decorator.ts     |   6 +-
 3 files changed, 77 insertions(+), 58 deletions(-)

diff --git a/src/auto-aspect-executor.ts b/src/auto-aspect-executor.ts
index 0d934ea..ddf6fbe 100644
--- a/src/auto-aspect-executor.ts
+++ b/src/auto-aspect-executor.ts
@@ -2,7 +2,7 @@ import { Injectable, OnModuleInit } from '@nestjs/common';
 import { DiscoveryService, MetadataScanner, Reflector } from '@nestjs/core';
 import { InstanceWrapper } from '@nestjs/core/injector/instance-wrapper';
 import { ASPECT } from './aspect';
-import { AnyFunction } from './core/types';
+import { AopMetadata } from './core/types';
 import { LazyDecorator } from './lazy-decorator';
 
 /**
@@ -18,6 +18,10 @@ export class AutoAspectExecutor implements OnModuleInit {
   ) {}
 
   onModuleInit() {
+    this.bootstrapLazyDecorators();
+  }
+
+  private bootstrapLazyDecorators() {
     const controllers = this.discoveryService.getControllers();
     const providers = this.discoveryService.getProviders();
 
@@ -30,66 +34,77 @@ export class AutoAspectExecutor implements OnModuleInit {
       .concat(controllers)
       .filter(({ instance }) => instance && Object.getPrototypeOf(instance));
 
-    for (const wrapper of instanceWrappers) {
-      const target = wrapper.isDependencyTreeStatic()
-        ? wrapper.instance
-        : wrapper.metatype.prototype;
+    for (const lazyDecorator of lazyDecorators) {
+      for (const wrapper of instanceWrappers) {
+        this.applyLazyDecorator(lazyDecorator, wrapper);
+      }
+    }
+  }
 
-      // Use scanFromPrototype for support nestjs 8
-      const methodNames = this.metadataScanner.scanFromPrototype(
-        target,
-        wrapper.isDependencyTreeStatic() ? Object.getPrototypeOf(target) : target,
-        (name) => name,
+  private applyLazyDecorator(lazyDecorator: LazyDecorator, instanceWrapper: InstanceWrapper<any>) {
+    const target = instanceWrapper.isDependencyTreeStatic()
+      ? instanceWrapper.instance
+      : instanceWrapper.metatype.prototype;
+
+    // Use scanFromPrototype for support nestjs 8
+    const methodNames = this.metadataScanner.scanFromPrototype(
+      target,
+      instanceWrapper.isDependencyTreeStatic() ? Object.getPrototypeOf(target) : target,
+      (name) => name,
+    );
+
+    const metadataKey = this.reflector.get(ASPECT, lazyDecorator.constructor);
+    // instance에 method names 를 순회하면서 lazyDecorator.wrap을 적용함
+    for (const methodName of methodNames) {
+      const metadataList: AopMetadata[] = this.reflector.get<AopMetadata[]>(
+        metadataKey,
+        target[methodName],
       );
+      if (!metadataList) {
+        return;
+      }
 
-      for (const methodName of methodNames) {
-        lazyDecorators.forEach((lazyDecorator) => {
-          const metadataKey = this.reflector.get(ASPECT, lazyDecorator.constructor);
-
-          const metadataList: {
-            originalFn: AnyFunction;
-            metadata?: unknown;
-            aopSymbol: symbol;
-          }[] = this.reflector.get<
-            {
-              originalFn: AnyFunction;
-              metadata?: unknown;
-              aopSymbol: symbol;
-            }[]
-          >(metadataKey, target[methodName]);
-          if (!metadataList) {
-            return;
-          }
-
-          for (const item of metadataList) {
-            const { originalFn, metadata, aopSymbol } = item;
-
-            // eslint-disable-next-line @typescript-eslint/no-this-alias
-            const self = this;
-            function wrap(this: object, ...args: unknown[]) {
-              const cached = self.wrappedMethodCache.get(item);
-              if (cached) {
-                return cached.apply(this, args);
-              }
-
-              const wrappedMethod = lazyDecorator.wrap({
-                instance: this,
-                methodName,
-                method: originalFn.bind(this),
-                metadata,
-              });
-              self.wrappedMethodCache.set(this, wrappedMethod);
-              return wrappedMethod.apply(this, args);
-            }
-
-            target[aopSymbol] ??= {};
-            target[aopSymbol][methodName] = wrap;
-          }
-        });
+      for (const aopMetadata of metadataList) {
+        this.wrapMethod({ lazyDecorator, aopMetadata, methodName, target });
       }
     }
   }
 
+  private wrapMethod({
+    lazyDecorator,
+    aopMetadata,
+    methodName,
+    target,
+  }: {
+    lazyDecorator: LazyDecorator;
+    aopMetadata: AopMetadata;
+    methodName: string;
+    target: any;
+  }) {
+    const { originalFn, metadata, aopSymbol } = aopMetadata;
+
+    // eslint-disable-next-line @typescript-eslint/no-this-alias
+    const self = this;
+    function wrappedFunction(this: object, ...args: unknown[]) {
+      const cached = self.wrappedMethodCache.get(aopMetadata);
+      if (cached) {
+        return cached.apply(this, args);
+      }
+
+      const wrappedMethod = lazyDecorator.wrap({
+        instance: this,
+        methodName,
+        method: originalFn.bind(this),
+        metadata,
+      });
+      self.wrappedMethodCache.set(this, wrappedMethod);
+      return wrappedMethod.apply(this, args);
+    }
+
+    target[aopSymbol] ??= {};
+    target[aopSymbol][methodName] = wrappedFunction;
+  }
+
   private lookupLazyDecorators(providers: InstanceWrapper[]): LazyDecorator[] {
     const { reflector } = this;
 
diff --git a/src/core/types.ts b/src/core/types.ts
index 284bdd8..b88de51 100644
--- a/src/core/types.ts
+++ b/src/core/types.ts
@@ -1 +1,7 @@
 export type AnyFunction = (...args: unknown[]) => unknown;
+
+export type AopMetadata = {
+  originalFn: AnyFunction;
+  metadata?: unknown;
+  aopSymbol: symbol;
+};
diff --git a/src/create-decorator.ts b/src/create-decorator.ts
index 77c30cf..0330000 100644
--- a/src/create-decorator.ts
+++ b/src/create-decorator.ts
@@ -1,4 +1,5 @@
 import { applyDecorators } from '@nestjs/common';
+import { AopMetadata } from './core/types';
 import { AddMetadata } from './utils';
 
 /**
@@ -13,10 +14,7 @@ export const createDecorator = (
   return applyDecorators(
     // 1. Add metadata to the method
     (target: object, propertyKey: string | symbol, descriptor: PropertyDescriptor) => {
-      return AddMetadata<
-        symbol | string,
-        { metadata?: unknown; aopSymbol: symbol; originalFn: unknown }
-      >(metadataKey, {
+      return AddMetadata<symbol | string, AopMetadata>(metadataKey, {
         originalFn: descriptor.value,
         metadata,
         aopSymbol,