Merge pull request #5 from maxgfr/maxgfr/async-hooks

Author: maxgfr

README.md

@@ -2,6 +2,8 @@
 
 `node-simple-context` is an helper to create a context in node.
 
+This library is highly inspired by [nctx](https://github.com/devthejo/nctx).
+
 ## Installation
 
 ```sh
@@ -40,39 +42,43 @@ console.log(contextA.get('xxx')); // undefined
 
 ### Complex
 
+#### With [`async_hooks`](https://nodejs.org/api/async_hooks.html)
+
 ```ts
 const context = createSimpleContext();
 
-const func = (forkId: string): string => {
-  const foo = context.getForkProperty(forkId, 'foo');
+const func = (): string => {
+  const foo = context.getForkProperty('foo');
   return `foo=${foo}`;
 };
 
-context.fork('X');
-context.setForkProperty('X', 'foo', 'bar');
+context.fork();
+context.setForkProperty('foo', 'bar');
 
 const res = await Promise.all([
   new Promise((resolve) => {
-    context.fork('A');
-    context.setForkProperty('A', 'foo', 'tata'),
-      setTimeout(() => {
-        resolve(func('A'));
-      }, 400);
+    setTimeout(() => {
+      context.fork();
+      context.setForkProperty('foo', 'tata');
+      resolve(func());
+    }, 400);
   }),
-  func('X'),
+  func(),
   new Promise((resolve) => {
-    context.fork('B');
-    context.setForkProperty('B', 'foo', 'toto'),
-      setTimeout(() => {
-        resolve(func('B'));
-      }, 200);
+    setTimeout(() => {
+      context.fork();
+      context.setForkProperty('foo', 'toto');
+      resolve(func());
+    }, 200);
   }),
 ]);
 
 console.log(res); // ['foo=tata', 'foo=bar', 'foo=toto']
 ```
 
-To achieve this, you can also define multiple contexts in the same file, like that:
+#### Without [`async_hooks`](https://nodejs.org/api/async_hooks.html)
+
+Here, I define multiple contexts in the same file, like that:
 
 ```ts
 const contextA = createSimpleContext();
@@ -88,21 +94,19 @@ contextC.setProperty('foo', 'bar');
 
 const res = await Promise.all([
   new Promise((resolve) => {
-    contextA.setProperty('foo', 'tata'),
-      setTimeout(() => {
-        resolve(func(contextA));
-      }, 400);
+    setTimeout(() => {
+      contextA.setProperty('foo', 'tata');
+      resolve(func(contextA));
+    }, 400);
   }),
   func(contextC),
   new Promise((resolve) => {
-    contextB.setProperty('foo', 'toto'),
-      setTimeout(() => {
-        resolve(func(contextB));
-      }, 200);
+    setTimeout(() => {
+      contextB.setProperty('foo', 'toto');
+      resolve(func(contextB));
+    }, 200);
   }),
 ]);
 
 console.log(res); // ['foo=tata', 'foo=bar', 'foo=toto']
 ```
-
-:warning: Otherwise, I advice you to use [nctx](https://github.com/devthejo/nctx) which uses `async_hooks` to detect dynamically the context in asynchronous call.

src/__tests__/context.test.ts

@@ -9,29 +9,29 @@ describe('SimpleContext', () => {
   it('should display value in order with fork', async () => {
     const context = createSimpleContext();
 
-    const func = (forkId: string): string => {
-      const foo = context.getForkProperty(forkId, 'foo');
+    const func = (): string => {
+      const foo = context.getForkProperty('foo');
       return `foo=${foo}`;
     };
 
-    context.fork('X');
-    context.setForkProperty('X', 'foo', 'bar');
+    context.fork();
+    context.setForkProperty('foo', 'bar');
 
     const res = await Promise.all([
       new Promise((resolve) => {
-        context.fork('A');
-        context.setForkProperty('A', 'foo', 'tata'),
-          setTimeout(() => {
-            resolve(func('A'));
-          }, 400);
+        setTimeout(() => {
+          context.fork();
+          context.setForkProperty('foo', 'tata');
+          resolve(func());
+        }, 400);
       }),
-      func('X'),
+      func(),
       new Promise((resolve) => {
-        context.fork('B');
-        context.setForkProperty('B', 'foo', 'toto'),
-          setTimeout(() => {
-            resolve(func('B'));
-          }, 200);
+        setTimeout(() => {
+          context.fork();
+          context.setForkProperty('foo', 'toto');
+          resolve(func());
+        }, 200);
       }),
     ]);
     expect(res).toStrictEqual(['foo=tata', 'foo=bar', 'foo=toto']);
@@ -51,17 +51,17 @@ describe('SimpleContext', () => {
 
     const res = await Promise.all([
       new Promise((resolve) => {
-        contextA.setProperty('foo', 'tata'),
-          setTimeout(() => {
-            resolve(func(contextA));
-          }, 400);
+        setTimeout(() => {
+          contextA.setProperty('foo', 'tata');
+          resolve(func(contextA));
+        }, 400);
       }),
       func(contextC),
       new Promise((resolve) => {
-        contextB.setProperty('foo', 'toto'),
-          setTimeout(() => {
-            resolve(func(contextB));
-          }, 200);
+        setTimeout(() => {
+          contextB.setProperty('foo', 'toto');
+          resolve(func(contextB));
+        }, 200);
       }),
     ]);
     expect(res).toStrictEqual(['foo=tata', 'foo=bar', 'foo=toto']);

src/context.ts

@@ -1,4 +1,5 @@
 import { randomUUID } from 'crypto';
+import async_hooks from 'async_hooks';
 
 export class SimpleContext {
   private contextId: string;
@@ -17,18 +18,23 @@ export class SimpleContext {
     this.properties[key] = value;
   }
 
-  public fork(id: string): void {
+  public fork(): void {
+    const id = async_hooks.executionAsyncId().toString();
     this.forks = [...this.forks, new SimpleContext(id)];
   }
 
-  public setForkProperty(id: string, key: string, value: any): void {
-    const fork = this.forks.find((fork) => fork.contextId === id);
-    if (fork) {
-      fork.setProperty(key, value);
+  public setForkProperty(key: string, value: any): void {
+    const id = async_hooks.executionAsyncId().toString();
+    if (id) {
+      const fork = this.forks.find((fork) => fork.contextId === id);
+      if (fork) {
+        fork.setProperty(key, value);
+      }
     }
   }
 
-  public getForkProperty(id: string, key: string): any {
+  public getForkProperty(key: string): any {
+    const id = async_hooks.executionAsyncId().toString();
     const fork = this.forks.find((fork) => fork.contextId === id);
     if (fork) {
       return fork.getProperty(key);