refactor: trait packet helpers

packages/entity/trait/index.js

@@ -27,6 +27,15 @@ export class Trait extends decorate(class {}) {
     }
   }
 
+  createTraitPacketUpdates(Packet) {
+    const packets = [];
+    if (this.isDirty) {
+      packets.push(new Packet(this.state, this.entity));
+      this.makeClean();
+    }
+    return packets;
+  }
+
   destroy() {}
 
   hooks() {
@@ -37,6 +46,15 @@ export class Trait extends decorate(class {}) {
     return Promise.resolve();
   }
 
+  get isDirty() {
+    for (const key in this.state) {
+      if (this.state[key] !== this.previousState[key]) {
+        return true;
+      }
+    }
+    return false;
+  }
+
   label() {
     return this.constructor.name;
   }
@@ -45,6 +63,12 @@ export class Trait extends decorate(class {}) {
     return {};
   }
 
+  makeClean() {
+    for (const key in this.state) {
+      this.previousState[key] = this.state[key];
+    }
+  }
+
   memoizedListeners() {
     if (!this._memoizedListeners) {
       this._memoizedListeners = this.listeners();

packages/entity/traits/directional.trait.js

@@ -41,14 +41,7 @@ export class Directional extends decorate(Trait) {
   }
 
   packetsForUpdate() {
-    const packets = [];
-    if (this.state.direction !== this.previousState.direction) {
-      packets.push(new TraitDirectionalPacket({
-        direction: this.state.direction,
-      }, this.entity));
-      this.previousState.direction = this.state.direction;
-    }
-    return packets;
+    return this.createTraitPacketUpdates(TraitDirectionalPacket);
   }
 
   listeners() {

packages/entity/traits/positioned.trait.js

@@ -74,10 +74,7 @@ export class Positioned extends decorate(Trait) {
 
   packetsForUpdate() {
     const packets = [];
-    if (
-      this.state.x !== this.previousState.x
-      || this.state.y !== this.previousState.y
-    ) {
+    if (this.isDirty) {
       // Physics slop can end us up with negatives. Don't allow them in the
       // packed representation, even though it means a slight loss in accuracy.
       // The world bounds will (should!) keep things *eventually* correct.
@@ -87,8 +84,7 @@ export class Positioned extends decorate(Trait) {
       packets.push(new TraitPositionedPacket({
         position: packed,
       }, this.entity));
-      this.previousState.x = this.state.x;
-      this.previousState.y = this.state.y;
+      this.makeClean();
     }
     return packets;
   }

packages/timing/traits/animated.trait.js

@@ -151,19 +151,7 @@ export class Animated extends decorate(Trait) {
   }
 
   packetsForUpdate() {
-    const packets = [];
-    if (
-      this.state.currentAnimation !== this.previousState.currentAnimation
-      || this.state.isAnimating !== this.previousState.isAnimating
-    ) {
-      packets.push(new TraitAnimatedPacket({
-        currentAnimation: this.state.currentAnimation,
-        isAnimating: this.state.isAnimating,
-      }, this.entity));
-      this.previousState.currentAnimation = this.state.currentAnimation;
-      this.previousState.isAnimating = this.state.isAnimating;
-    }
-    return packets;
+    return this.createTraitPacketUpdates(TraitAnimatedPacket);
   }
 
   setSpriteScale() {