Fixed chip.Alternative and bumped version to 3.0.6

.eslintrc.js

@@ -20,6 +20,7 @@ module.exports = {
   rules: {
     "no-console": "off",
     "no-unused-vars": ["error", { args: "none" }],
+    "@typescript-eslint/no-non-null-assertion": "off",
   },
   ignorePatterns: [".eslintrc.js"],
 };

package.json

@@ -1,6 +1,6 @@
 {
   "name": "booyah",
-  "version": "3.0.5",
+  "version": "3.0.6",
   "description": "HTML5 game engine",
   "scripts": {
     "build": "tsc",

src/chip.ts

@@ -291,7 +291,7 @@ export abstract class ChipBase extends EventEmitter implements Chip {
     if (this._state !== "active" && this._state !== "paused")
       throw new Error(`terminate() called from state ${this._state}`);
 
-    this._outputSignal = outputSignal ?? makeSignal();
+    this._outputSignal = outputSignal;
     this._onTerminate();
 
     this._unsubscribe(); // Remove all event listeners
@@ -577,14 +577,26 @@ export abstract class Composite extends ChipBase {
   }
 
   public terminate(outputSignal: Signal = makeSignal()): void {
+    // Can't just call super.terminate() here, the order is slightly different
+
+    if (this._state !== "active" && this._state !== "paused")
+      throw new Error(`terminate() called from state ${this._state}`);
+
     if (this._methodCallInProgress) {
       this._deferredOutputSignal = outputSignal;
       return;
     }
 
+    this._state = "inactive";
+
+    this._unsubscribe(); // Remove all event listeners
+
     this._terminateAllChildChips();
 
-    super.terminate(outputSignal);
+    this._outputSignal = outputSignal;
+    this._onTerminate();
+
+    this.emit("terminated", this._outputSignal);
   }
 
   public pause(tickInfo: TickInfo): void {
@@ -1500,27 +1512,21 @@ export class Alternative extends Composite {
   }
 
   _onActivate() {
-    for (const chipActivationInfo of this._chipActivationInfos) {
+    for (let i = 0; i < this._chipActivationInfos.length; i++) {
+      const chipActivationInfo = this._chipActivationInfos[i];
+
+      this._subscribe(chipActivationInfo.chip, "terminated", () =>
+        this._onChildTerminated(i)
+      );
       this._activateChildChip(chipActivationInfo.chip, {
         context: chipActivationInfo.context,
       });
     }
-
-    this._checkForSignal();
   }
 
-  _onTick() {
-    this._checkForSignal();
-  }
-
-  private _checkForSignal(): void {
-    for (let i = 0; i < this._chipActivationInfos.length; i++) {
-      if (this._childChips[i].outputSignal) {
-        const terminateWith =
-          this._chipActivationInfos[i].signal ?? makeSignal(i.toString());
-        this.terminate(terminateWith);
-        break;
-      }
-    }
+  private _onChildTerminated(index: number) {
+    const terminateWith =
+      this._chipActivationInfos[index].signal ?? makeSignal(index.toString());
+    this.terminate(terminateWith);
   }
 }

tests/chip.test.ts

@@ -811,6 +811,46 @@ describe("StateMachine", () => {
   });
 });
 
+describe("Alternative", () => {
+  test("picks the first chip that terminates", () => {
+    const children = [new MockChip(), new MockChip()];
+
+    const alternative = new chip.Alternative(children);
+
+    // Run once
+    alternative.activate(makeFrameInfo(), makeChipContext(), makeSignal());
+    alternative.tick(makeFrameInfo());
+
+    // Terminate second child
+    children[1].terminate();
+
+    // Alternative should terminate as well, with an output signal of the index of the child
+    expect(alternative.state).toBe("inactive");
+    expect(alternative.outputSignal.name).toBe("1");
+  });
+
+  test("can provide custom signal", () => {
+    const children = [
+      { chip: new MockChip(), signal: chip.makeSignal("hello") },
+      new MockChip(),
+    ];
+
+    const alternative = new chip.Alternative(children);
+
+    // Run once
+    alternative.activate(makeFrameInfo(), makeChipContext(), makeSignal());
+    alternative.tick(makeFrameInfo());
+
+    // Terminate first child
+    // @ts-ignore
+    children[0].chip.terminate();
+
+    // Alternative should terminate as well, with an output signal of the index of the child
+    expect(alternative.state).toBe("inactive");
+    expect(alternative.outputSignal.name).toBe("hello");
+  });
+});
+
 //// Test hot reload features
 
 class ReloadingChip extends chip.ChipBase {