refactor: immutable optimizations

packages/entity/list.js

@@ -97,10 +97,12 @@ export class EntityList extends decorate(Synchronized) {
       const entity = this._entities[uuid];
       entity.tick(elapsed);
     }
-    for (const uuid in this._entities) {
-      const entity = this._entities[uuid];
-      this.state = this.state.set(uuid, entity.state);
-    }
+    this.state = this.state.withMutations((state) => {
+      for (const uuid in this._entities) {
+        const entity = this._entities[uuid];
+        state.set(uuid, entity.state);
+      }
+    });
   }
 
   visibleEntities(query) {

packages/state/synchronized.js

@@ -56,16 +56,22 @@ export class Synchronized extends decorate(class {}) {
   }
 
   tick(elapsed) {
-    for (const key of this.synchronizedChildren()) {
+    const children = this.synchronizedChildren();
+    for (const key of children) {
       if (this[key] instanceof Synchronized) {
         this[key].tick(elapsed);
-        this.state = this.state.set(key, this[key].state);
-      }
-      else {
-        this.state = this.state.set(key, this[key]);
       }
     }
-
+    this.state = this.state.withMutations((state) => {
+      for (const key of children) {
+        if (this[key] instanceof Synchronized) {
+          state.set(key, this[key].state);
+        }
+        else {
+          state.set(key, this[key]);
+        }
+      }
+    });
   }
 
 }

packages/state/synchronizer.js

@@ -36,8 +36,13 @@ export class Synchronizer {
     for (const key in this._statefuls) {
       const stateful = this._statefuls[key];
       stateful.tick(elapsed);
-      this._state = this._state.set(key, stateful.state);
     }
+    this._state = this._state.withMutations((state) => {
+      for (const key in this._statefuls) {
+        const stateful = this._statefuls[key];
+        state.set(key, stateful.state);
+      }
+    });
   }
 
 }

packages/topdown/layers.js

@@ -115,8 +115,13 @@ export class Layers extends decorate(Synchronized) {
       for (const index in this.layers) {
         const layer = this.layers[index];
         layer.tick(elapsed);
-        this.state = this.state.set(index, layer.state);
       }
+      this.state = this.state.withMutations((state) => {
+        for (const index in this.layers) {
+          const layer = this.layers[index];
+          state.set(index, layer.state);
+        }
+      });
     }
   }