refactor: move engine's start() to separate file

client/src/composables/engine/start.ts

@@ -0,0 +1,9 @@
+export default function (): void {
+    if (this.isActive.value && !this.shouldStop.value) {
+        console.warn('attempt to start already running engine!')
+        return
+    }
+    this.isActive.value = true
+    this.shouldStop.value = false
+    console.log('start engine')
+}

client/src/composables/useEngine.ts

@@ -1,4 +1,11 @@
 import { useState } from '#app'
+import { Ref } from 'vue'
+import start from '@/composables/engine/start'
+
+interface EngineContext {
+    isActive: Ref<boolean>
+    shouldStop: Ref<boolean>
+}
 
 export interface useEngine {
     start(): void
@@ -6,23 +13,16 @@ export interface useEngine {
 }
 
 export default (): useEngine => {
-    const isActive = useState('engine__is-active', () => false)
+    const context: EngineContext = {
-    const shouldStop = useState('engine__should-stop', () => false)
+        isActive: useState('engine__is-active', () => false),
+        shouldStop: useState('engine__should-stop', () => false),
+    }
 
     return {
-        start: (): void => {
+        start: () => start.apply(context),
-            if (isActive.value && !shouldStop.value) {
-                console.warn('attempt to start already running engine!')
-                return
-            }
-            isActive.value = true
-            shouldStop.value = false
-            console.log('start engine')
-        },
-
         stop: (): void => {
-            if (isActive.value) {
+            if (context.isActive.value) {
-                shouldStop.value = true
+                context.shouldStop.value = true
                 console.log('shut down engine')
             }
         },