refactor: simplify splice

app/ecs/components/ticking.js

@@ -4,29 +4,23 @@ export default class Ticking extends Component {
   instanceFromSchema() {
     return class TickingInstance extends super.instanceFromSchema() {
 
-      $$finished = [];
       $$tickers = [];
 
       add(ticker) {
         this.$$tickers.push(ticker);
         ticker.then(() => {
-          this.$$finished.push(ticker);
-        });
-      }
-
-      destroy() {
-        this.$$finished = [];
-        this.$$tickers = [];
-      }
-
-      tick(elapsed) {
-        for (const ticker of this.$$finished) {
           this.$$tickers.splice(
             this.$$tickers.indexOf(ticker),
             1,
           );
-        }
-        this.$$finished = [];
+        });
+      }
+
+      destroy() {
+        this.$$tickers = [];
+      }
+
+      tick(elapsed) {
         for (const ticker of this.$$tickers) {
           ticker.tick(elapsed);
         }