chore: well the book was obviously wrong.

permalink: http://whatthecommit.com/3f3725962c1b9d44b824736db7579209

packages/ioc/package.json

@@ -4,7 +4,7 @@
   "description": "Dependency Injection system",
   "main": "dist/index.js",
   "scripts": {
-    "test": "vitest --run",
+    "test": "vitest --watch",
     "tdd": "vitest",
     "build": "tsc"
   },

packages/ioc/src/container.ts

@@ -82,14 +82,16 @@ export class Container {
 
         const existing = this.__singletons.get(key);
         if (!existing) {
-            // @jacoobes should we return false if no existing key?
-            throw Error("No existing key to swap for " + key);
+            return false;
         }
         // check if there's dispose hook, and call it
         if (hasCallableMethod(existing, 'dispose')) {
-            this.disposeAll().then(() => {;
-                this.registerHooks('dispose', swp);
-            });
+            existing.dispose();
+            // get the index of the existing singleton, now delete the dispose hook at that index
+            const hookIndex = this.hooks.get('dispose')!.indexOf(existing.dispose);
+            if (hookIndex > -1) {
+                this.hooks.get('dispose')!.splice(hookIndex, 1);
+            }
         }
 
         this.__singletons.set(key, swp);

packages/ioc/test/index.test.ts

@@ -125,8 +125,9 @@ describe('CoreContainer Tests', () => {
         expect(singletonWInit.init).toHaveBeenCalledOnce();
     });
 
-    it('should throw because not swapping anything', () => {
-        expect(() => coreContainer.swap('singletonKeyWithInit', singletonWInit)).toThrow()
+    it('should be false because not swapping anything', () => {
+        const swap = coreContainer.swap('singletonKeyWithInit', singletonWInit);
+        expect(swap).toBe(false);
     })
 
     it('should swap object with another', () => {
@@ -146,11 +147,18 @@ describe('CoreContainer Tests', () => {
             dispose: vi.fn()
         };
 
+        const singletonWithDispose3 = {
+            value: 'singletonValueWithDispose3',
+            dispose: vi.fn()
+        };
+
+        coreContainer.addSingleton('singletonWithDispose3', singletonWithDispose3);
         const swapped = coreContainer.swap('singleton', singletonWithDispose2);
 
         expect(singletonWDispose.dispose).toHaveBeenCalledOnce();
         expect(coreContainer.get<Record<string, unknown>>('singleton')).toBe(singletonWithDispose2);
         expect(singletonWithDispose2.dispose).not.toHaveBeenCalledOnce();
+        expect(singletonWithDispose3.dispose).not.toHaveBeenCalledOnce();
         expect(swapped).toBe(true);
     })
 })

yarn.lock

@@ -2278,7 +2278,7 @@ __metadata:
 
 "typescript@patch:typescript@^5.0.0#~builtin<compat/typescript>":
   version: 5.4.5
-  resolution: "typescript@patch:typescript@npm%3A5.4.5#~builtin<compat/typescript>::version=5.4.5&hash=14eedb"
+  resolution: "typescript@patch:typescript@npm%3A5.4.5#~builtin<compat/typescript>::version=5.4.5&hash=f3b441"
   bin:
     tsc: bin/tsc
     tsserver: bin/tsserver