simplify unsubscribe

robertpenner · Apr 28, 2017 · 92a92e0 · 92a92e0
1 parent a283571
commit 92a92e0
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Showing 4 changed files with 19 additions and 23 deletions.
diff --git a/src/nanosignal.ts b/src/nanosignal.ts
@@ -5,8 +5,8 @@ export interface Listener<PAYLOAD, RESULT = void> {
 /**
  * Cancels a listener's subscription to its signal.
  */
-export interface Subscription {
-  unsubscribe(): void;
+export interface Unsubscriber {
+  (): void;
 }
 
 export interface Signal<PAYLOAD, RESULT = void> {
@@ -16,7 +16,7 @@ export interface Signal<PAYLOAD, RESULT = void> {
    * Starts a function listening to this signal.
    * @param listener
    */
-  subscribe(listener: Listener<PAYLOAD, RESULT>): Subscription;
+  subscribe(listener: Listener<PAYLOAD, RESULT>): Unsubscriber;
 }
 
 /**
@@ -30,10 +30,8 @@ export default function createSignal<PAYLOAD, RESULT = void>(firstListener?: Lis
 
   signal.subscribe = (listener) => {
     listeners = listeners.concat(listener);
-    return {
-      unsubscribe() {
-        listeners = listeners.filter(fn => fn !== listener);
-      }
+    return () => {
+      listeners = listeners.filter(fn => fn !== listener);
     };
   };
 

diff --git a/src/nanosignal0.ts b/src/nanosignal0.ts
@@ -5,8 +5,8 @@ export interface Listener0<RESULT = void> {
 /**
  * Cancels a listener's subscription to its signal.
  */
-export interface Subscription {
-  unsubscribe(): void;
+export interface Unsubscriber {
+  (): void;
 }
 
 export interface Signal0<RESULT = void> {
@@ -16,7 +16,7 @@ export interface Signal0<RESULT = void> {
    * Starts a function listening to this signal.
    * @param listener
    */
-  subscribe(listener: Listener0<RESULT>): Subscription;
+  subscribe(listener: Listener0<RESULT>): Unsubscriber;
 }
 
 /**
@@ -30,10 +30,8 @@ export default function createSignal0<RESULT = void>(firstListener?: Listener0<R
 
   signal.subscribe = (listener) => {
     listeners = listeners.concat(listener);
-    return {
-      unsubscribe() {
-        listeners = listeners.filter(fn => fn !== listener);
-      }
+    return () => {
+      listeners = listeners.filter(fn => fn !== listener);
     };
   };
 

diff --git a/test/nanosignal-self-removal.test.ts b/test/nanosignal-self-removal.test.ts
@@ -8,8 +8,8 @@ describe('when a listener unsubscribes another listener during dispatch', () =>
   beforeEach(() => {
     happened = createSignal0();
     listenerA = jest.fn();
-    const subscriptionA = happened.subscribe(listenerA);
-    listenerB = jest.fn(subscriptionA.unsubscribe);
+    const unsubscribeA = happened.subscribe(listenerA);
+    listenerB = jest.fn(unsubscribeA);
     listenerC = jest.fn();
     happened.subscribe(listenerB);
     happened.subscribe(listenerC);

diff --git a/test/nanosignal-signal0.test.ts b/test/nanosignal-signal0.test.ts
@@ -1,4 +1,4 @@
-import createSignal0, { Signal0, Subscription } from '../src/nanosignal0';
+import createSignal0, { Signal0, Unsubscriber } from '../src/nanosignal0';
 
 describe('signal with 0 arguments', () => {
   let happened: Signal0;
@@ -9,11 +9,11 @@ describe('signal with 0 arguments', () => {
 
   describe('when removing a listener before firing', () => {
     let listenerA: jest.Mock<any>;
-    let subscriptionA: Subscription;
+    let removeA: Unsubscriber;
     beforeEach(() => {
       listenerA = jest.fn();
-      subscriptionA = happened.subscribe(listenerA);
-      subscriptionA.unsubscribe();
+      removeA = happened.subscribe(listenerA);
+      removeA();
       happened();
     });
 
@@ -24,10 +24,10 @@ describe('signal with 0 arguments', () => {
 
   describe('when adding the same listener twice', () => {
     let listenerA: jest.Mock<any>;
-    let subscriptionA: Subscription;
+    let removeA: () => void;
     beforeEach(() => {
       listenerA = jest.fn();
-      subscriptionA = happened.subscribe(listenerA);
+      removeA = happened.subscribe(listenerA);
       happened.subscribe(listenerA);
     });
 
@@ -42,7 +42,7 @@ describe('signal with 0 arguments', () => {
 
     describe('then removing the listener once and firing', () => {
       beforeEach(() => {
-        subscriptionA.unsubscribe();
+        removeA();
         happened();
       });
       it('the listener is not called', () => {