perf(core): optimize context switching with lazy caching

Author: devizi0

packages/core/helpers/execution-context-host.ts

@@ -9,6 +9,9 @@ import {
 
 export class ExecutionContextHost implements ExecutionContext {
   private contextType = 'http';
+  private httpCache?: HttpArgumentsHost;
+  private rpcCache?: RpcArgumentsHost;
+  private wsCache?: WsArgumentsHost;
 
   constructor(
     private readonly args: any[],
@@ -41,25 +44,34 @@ export class ExecutionContextHost implements ExecutionContext {
   }
 
   switchToRpc(): RpcArgumentsHost {
-    return Object.assign(this, {
-      getData: () => this.getArgByIndex(0),
-      getContext: () => this.getArgByIndex(1),
-    });
+    if (!this.rpcCache) {
+      this.rpcCache = Object.assign(this, {
+        getData: () => this.getArgByIndex(0),
+        getContext: () => this.getArgByIndex(1),
+      });
+    }
+    return this.rpcCache;
   }
 
   switchToHttp(): HttpArgumentsHost {
-    return Object.assign(this, {
-      getRequest: () => this.getArgByIndex(0),
-      getResponse: () => this.getArgByIndex(1),
-      getNext: () => this.getArgByIndex(2),
-    });
+    if (!this.httpCache) {
+      this.httpCache = Object.assign(this, {
+        getRequest: () => this.getArgByIndex(0),
+        getResponse: () => this.getArgByIndex(1),
+        getNext: () => this.getArgByIndex(2),
+      });
+    }
+    return this.httpCache;
   }
 
   switchToWs(): WsArgumentsHost {
-    return Object.assign(this, {
-      getClient: () => this.getArgByIndex(0),
-      getData: () => this.getArgByIndex(1),
-      getPattern: () => this.getArgByIndex(this.getArgs().length - 1),
-    });
+    if (!this.wsCache) {
+      this.wsCache = Object.assign(this, {
+        getClient: () => this.getArgByIndex(0),
+        getData: () => this.getArgByIndex(1),
+        getPattern: () => this.getArgByIndex(this.getArgs().length - 1),
+      });
+    }
+    return this.wsCache;
   }
 }

packages/core/test/helpers/execution-context-host.spec.ts

@@ -48,6 +48,12 @@ describe('ExecutionContextHost', () => {
       expect(proxy.getData()).to.be.eq(args[0]);
       expect(proxy.getContext()).to.be.eq(args[1]);
     });
+
+    it('should return cached proxy on subsequent calls', () => {
+      const proxy1 = contextHost.switchToRpc();
+      const proxy2 = contextHost.switchToRpc();
+      expect(proxy1).to.equal(proxy2);
+    });
   });
 
   describe('switchToHttp', () => {
@@ -60,6 +66,12 @@ describe('ExecutionContextHost', () => {
       expect(proxy.getResponse()).to.be.eq(args[1]);
       expect(proxy.getNext()).to.be.eq(args[2]);
     });
+
+    it('should return cached proxy on subsequent calls', () => {
+      const proxy1 = contextHost.switchToHttp();
+      const proxy2 = contextHost.switchToHttp();
+      expect(proxy1).to.equal(proxy2);
+    });
   });
 
   describe('switchToWs', () => {
@@ -70,5 +82,11 @@ describe('ExecutionContextHost', () => {
       expect(proxy.getClient()).to.be.eq(args[0]);
       expect(proxy.getData()).to.be.eq(args[1]);
     });
+
+    it('should return cached proxy on subsequent calls', () => {
+      const proxy1 = contextHost.switchToWs();
+      const proxy2 = contextHost.switchToWs();
+      expect(proxy1).to.equal(proxy2);
+    });
   });
 });