Allow Event & AbortController to not exist

Author: RoyalIcing

package.json

@@ -23,7 +23,7 @@
     }
   },
   "scripts": {
-    "prepack": "jest && npm run build",
+    "prepack": "jest && npm run build && node tests/node.js",
     "dev": "parcel watch",
     "build": "parcel build",
     "test": "jest --watch"

src/index.ts

@@ -248,7 +248,7 @@ class InternalInstance {
   private globalHandlers = new Handlers()
   private resolved = null as Promise<Record<string, any>> | null
   private accumulations: Map<symbol | string, Array<symbol | string | Event>> = new Map();
-  private eventAborter = new AbortController();
+  private eventAborter = typeof AbortController !== 'undefined' ? new AbortController() : undefined;
   child: null | InternalInstance = null
 
   constructor(
@@ -334,14 +334,14 @@ class InternalInstance {
       // Not sure if we still need this if we have abort signals, and for what versions of Node/browsers?
       target.removeEventListener(event, this);
     }
-    this.eventAborter.abort();
+    this.eventAborter?.abort();
 
     this.globalHandlers.reset();
   }
 
   consume(stateGenerator: (() => StateDefinition) | (() => Generator<Yielded, StateDefinition, never>)) {
     this.cleanup();
-    this.eventAborter = new AbortController();
+    this.eventAborter = typeof AbortController !== 'undefined' ? new AbortController() : undefined;
 
     this.willEnter();
 
@@ -374,7 +374,7 @@ class InternalInstance {
       }
 
       for (const [event, target] of this.globalHandlers.eventsToListenTo) {
-        target.addEventListener(event, this, { signal: this.eventAborter.signal } as AddEventListenerOptions);
+        target.addEventListener(event, this, { signal: this.eventAborter?.signal } as AddEventListenerOptions);
       }
 
     } else if (typeof initialReturn === 'function') {
@@ -474,7 +474,15 @@ class InternalInstance {
   }
 }
 
-class MachineStateChangedEvent extends Event {
+const FallbackEvent = class Event {
+  public readonly type: string;
+  constructor(type: string, eventInitDict?: EventInit | undefined) {
+    this.type = type;
+  }
+} as typeof Event;
+const BaseEvent = typeof Event !== 'undefined' ? Event : FallbackEvent
+
+class MachineStateChangedEvent extends BaseEvent {
   readonly value: string;
 
   constructor(type: string, value: string) {
@@ -517,7 +525,7 @@ export function start(
         _aborter?.signal.dispatchEvent(new MachineStateChangedEvent('StateChanged', getCurrent() as string));
       },
       didChangeAccumulations() {
-        _aborter?.signal.dispatchEvent(new Event('AccumulationsChanged'));
+        _aborter?.signal.dispatchEvent(new BaseEvent('AccumulationsChanged'));
       },
       sendEvent(event, snapshotCount) {
         if (typeof snapshotCount === "number" && snapshotCount !== _changeCount) {

tests/node.js

@@ -0,0 +1,25 @@
+const assert = require('assert');
+const { start, on } = require("../dist/yieldmachine");
+
+function Switch() {
+  function* OFF() {
+    yield on("FLICK", ON);
+  }
+  function* ON() {
+    yield on("FLICK", OFF);
+  }
+
+  return OFF;
+}
+
+const machine = start(Switch);
+assert.ok(machine);
+assert.strictEqual(machine.current, "OFF");
+
+machine.next("FLICK");
+assert.strictEqual(machine.current, "ON");
+assert.strictEqual(machine.changeCount, 1);
+
+machine.next("FLICK");
+assert.strictEqual(machine.current, "OFF");
+assert.strictEqual(machine.changeCount, 2);