chore: tidy

packages/behavior/item/actions.js

@@ -16,7 +16,7 @@ export class Actions extends decorate(Traversals) {
   constructor() {
     super();
     this._index = 0;
-    this._pending = null;
+    this._actionPromise = null;
   }
 
   emitFinished() {
@@ -36,33 +36,34 @@ export class Actions extends decorate(Traversals) {
   }
 
   tick(context, elapsed) {
+    // Empty resolves immediately.
     if (this.traversals.length === 0) {
       this.emitFinished();
       return;
     }
-    if (this._pending) {
-      if (this._pending instanceof TickingPromise) {
-        this._pending.tick(elapsed);
-      }
+    // If the action promise ticks, tick it.
+    if (this._actionPromise && this._actionPromise instanceof TickingPromise) {
+      this._actionPromise.tick(elapsed);
       return;
     }
-
     // Actions execute immediately until a promise is made, or they're all
     // executed.
     while (true) {
+      // Run the action.
       const result = this.traversals[this.index].traverse(context);
+      // Deferred result.
       if (result instanceof Promise) {
-        result.then(() => {
+        this._actionPromise = result;
+        // Handle any errors.
+        result.catch(console.error).finally(() => {
+          // Finally, run the prologue.
           this.prologue();
         });
-        result.catch((error) => {
-          console.error(error);
-          this.prologue();
-        });
-        this._pending = result;
         break;
       }
+      // Immediate result.
       this.prologue();
+      // Need to break out immediately if required.
       if (0 === this.index) {
         break;
       }
@@ -70,15 +71,21 @@ export class Actions extends decorate(Traversals) {
   }
 
   parallel(context) {
+    // Map all traversals to results.
     const results = this.traversals.map((traversal) => {
       return traversal.traverse(context);
     });
+    // Wrap all results in a TickingPromise.
     return TickingPromise.all(results);
   }
 
   prologue() {
-    this._pending = null;
-    if (0 === (this.index = (this.index + 1) % this.traversals.length)) {
+    // Clear out the action promise.
+    this._actionPromise = null;
+    // Increment and wrap the index.
+    this.index = (this.index + 1) % this.traversals.length;
+    // If rolled over, the actions are finished.
+    if (0 === this.index) {
       this.emitFinished();
     }
   }
@@ -90,9 +97,7 @@ export class Actions extends decorate(Traversals) {
   tickingPromise(context) {
     return new TickingPromise(
       (resolve) => {
-        this.once('actionsFinished', () => {
-          resolve();
-        });
+        this.once('actionsFinished', resolve);
       },
       (elapsed) => {
         this.tick(context, elapsed);