From b42408d6c3053d86e15f8a63fd6048a8918bdc47 Mon Sep 17 00:00:00 2001
From: Hiroshiba <hihokaruta@gmail.com>
Date: Thu, 1 Aug 2024 02:26:17 +0900
Subject: [PATCH] =?UTF-8?q?=E3=83=88=E3=83=A9=E3=83=83=E3=82=AF=E3=82=92?=
 =?UTF-8?q?=E4=B8=8A=E6=9B=B8=E3=81=8D=E3=81=97=E3=81=A6=E3=82=A4=E3=83=B3?=
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---
 src/sing/domain.ts   |  3 ++-
 src/store/singing.ts | 11 ++++-------
 2 files changed, 6 insertions(+), 8 deletions(-)

diff --git a/src/sing/domain.ts b/src/sing/domain.ts
index fc85b72683..6d84530b73 100644
--- a/src/sing/domain.ts
+++ b/src/sing/domain.ts
@@ -21,7 +21,8 @@ const BEAT_TYPES = [2, 4, 8, 16];
 const MIN_BPM = 40;
 const MAX_SNAP_TYPE = 32;
 
-export const isTrackEmpty = (track: Track) => track.notes.length === 0;
+export const isTracksEmpty = (tracks: Track[]) =>
+  tracks.length === 0 || (tracks.length === 1 && tracks[0].notes.length === 0);
 
 export const isValidTpqn = (tpqn: number) => {
   return (
diff --git a/src/store/singing.ts b/src/store/singing.ts
index a5c84bd916..187620a989 100644
--- a/src/store/singing.ts
+++ b/src/store/singing.ts
@@ -76,7 +76,7 @@ import {
   isValidTrack,
   SEQUENCER_MIN_NUM_MEASURES,
   getNumMeasures,
-  isTrackEmpty,
+  isTracksEmpty,
   shouldPlayTracks,
 } from "@/sing/domain";
 import {
@@ -2762,7 +2762,7 @@ export const singingCommandStore = transformCommandStore(
       },
       /**
        * 複数のトラックを選択中のトラックの後ろに挿入し、テンポ情報などをインポートする。
-       * 選択中のトラックが空の場合は最初のトラックで上書きする。
+       * 空のプロジェクトならトラックを上書きする。
        */
       async action(
         { state, commit, getters, dispatch },
@@ -2778,11 +2778,8 @@ export const singingCommandStore = transformCommandStore(
             if (!isValidTrack(track)) {
               throw new Error("The track is invalid.");
             }
-            // 空のトラックなら上書きする
-            if (
-              i === 0 &&
-              isTrackEmpty(getOrThrow(state.tracks, prevTrackId))
-            ) {
+            // 空のプロジェクトならトラックを上書きする
+            if (i === 0 && isTracksEmpty([...state.tracks.values()])) {
               payload.push({
                 track,
                 trackId: prevTrackId,