offer aspectj-like around advice via new MethodMetadata.complete meth…

…od (#76) * offer aspectj-like around advice via new MethodMetadata.complete method * bump minor (to 0.8.0) * add test * fix typo * update package-lock.json
mgechev · Nov 15, 2018 · 1c03a12 · 1c03a12
1 parent a58040b
commit 1c03a12
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Showing 6 changed files with 58 additions and 8 deletions.
diff --git a/lib/src/advices/sync_advices.ts b/lib/src/advices/sync_advices.ts
@@ -1,5 +1,5 @@
-import { Advice } from '../core/advice';
-import { Metadata } from '../core/metadata';
+import { Advice } from "../core/advice";
+import { Metadata } from "../core/metadata";
 
 export class BeforeAdvice extends Advice {
   wove(target: Function, metadata: Metadata) {
@@ -19,9 +19,17 @@ export class AfterAdvice extends Advice {
 
 export class AroundAdvice extends Advice {
   wove(target: Function, metadata: Metadata) {
-    this.advice.bind(this.context, metadata).apply(null, metadata.method.args);
-    this.invoke(target, metadata);
-    this.advice.bind(this.context, metadata).apply(null, metadata.method.args);
+    // if the user called metadata.method.complete(), then he's handling return value himself;
+    // else he called metadata.method.invoke() & we'll handle it unless metadata.method.proceed is false
+    const result = this.advice.bind(this.context, metadata).apply(null, metadata.method.args);
+
+    if (metadata.method.proceed) {
+      this.invoke(target, metadata);
+      this.advice.bind(this.context, metadata).apply(null, metadata.method.args);
+    } else {
+      metadata.method.result = result;
+    }
+
     return metadata.method.result;
   }
 }

diff --git a/lib/src/core/join_point.ts b/lib/src/core/join_point.ts
@@ -32,15 +32,22 @@ export abstract class JoinPoint {
     context: any,
     woveMetadata: any
   ): Metadata {
+    const boundFn = fn.bind(context)
+
     var invocation: MethodMetadata = {
       name: key,
       proceed: true,
       context: context,
       result: undefined,
       exception: undefined,
       args: undefined,
-      invoke: fn.bind(context),
+      invoke: boundFn,
+      complete: function complete(...args: any[]): any {
+        this.method.proceed = false;
+        return boundFn.apply(null, args);
+      }
     };
+
     var metadata: Metadata = new Metadata();
     metadata.method = invocation;
     metadata.className = className;
@@ -53,6 +60,7 @@ export abstract class JoinPoint {
       metadata.method.context = previousMetadata.method.context;
     } else {
       metadata.method.args = Array.prototype.slice.call(args);
+      metadata.method.complete = metadata.method.complete.bind(metadata)
     }
     return metadata;
   }

diff --git a/lib/src/core/metadata.ts b/lib/src/core/metadata.ts
@@ -6,6 +6,7 @@ export class MethodMetadata {
   public result: any;
   public exception: any;
   public invoke: (...args: any[]) => any;
+  public complete: (...args: any[]) => any;
 }
 
 export class Metadata {

diff --git a/package-lock.json b/package-lock.json
diff --git a/package.json b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "aspect.js",
-  "version": "0.7.5",
+  "version": "0.8.0",
   "description": "Library for aspect-oriented programming with JavaScript",
   "main": "index.js",
   "typings": "index.d.ts",

diff --git a/test/advices/around_advice_using_complete.ts b/test/advices/around_advice_using_complete.ts
@@ -0,0 +1,33 @@
+import { Wove, resetRegistry, Metadata } from "../../lib/src/core";
+
+import { expect } from "chai";
+import { aroundMethod } from "../../lib";
+
+describe("around advices", () => {
+  afterEach(() => {
+    resetRegistry();
+  });
+
+  it("should only get invoked once when using MethodMetadata.complete()", () => {
+    let count = 0;
+
+    class Aspect {
+      @aroundMethod({ classNamePattern: /^Test/, methodNamePattern: /^get$/ })
+      aroundMethod(meta: Metadata) {
+        return meta.method.complete(...meta.method.args) + " appended from the aspect";
+      }
+    }
+
+    @Wove()
+    class Test {
+      get(it: string): string {
+        count++;
+        return it;
+      }
+    }
+
+    const test = new Test();
+    expect(test.get("test")).to.equal("test appended from the aspect");
+    expect(count).to.equal(1);
+  });
+});