update?

src/BeatUnit.ts

@@ -1,8 +1,59 @@
+export enum BeatUnitType {
+    Normal,
+    GhostNote,
+}
+
+
 export default class BeatUnit {
-    constructor() {
+    private on: boolean = false;
+    private type: BeatUnitType = BeatUnitType.Normal;
+    private onUpdateCallbacks: ((on: boolean, type: BeatUnitType) => void)[] = [];
+
+    constructor(on: boolean = false) {
+        this.on = on;
     }
 
     stringify(): string {
-        return "U";
+        if (!this.on) {
+            return "O";
+        }
+        if (this.type === BeatUnitType.GhostNote) {
+            return "G";
+        } else {
+            return "#";
+        }
+    }
+
+    toggle(): void {
+        this.on = !this.on;
+        this.notify();
+    }
+
+    setOn(on: boolean): void {
+        this.on = on;
+        this.notify();
+    }
+
+    setType(type: BeatUnitType) {
+        this.type = type;
+        this.notify();
+    }
+
+    getType(): BeatUnitType {
+        return this.type;
+    }
+
+    isOn(): boolean {
+        return this.on;
+    }
+
+    onUpdate(callback: (on: boolean, type: BeatUnitType) => void) {
+        this.onUpdateCallbacks.push(callback);
+    }
+
+    notify(): void {
+        for (const cb of this.onUpdateCallbacks) {
+            cb(this.on, this.type);
+        }
     }
 }