From 9e9f25ff800b50586a6e733f9efab8e011c02ba7 Mon Sep 17 00:00:00 2001
From: Xmader <xmader@outlook.com>
Date: Tue, 24 Nov 2020 02:59:19 -0500
Subject: [PATCH] feat: abstract storage for scoreinfo instance

---
 src/mscz.ts      | 5 ++++-
 src/scoreinfo.ts | 2 ++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/mscz.ts b/src/mscz.ts
index 999cba2..2733b00 100644
--- a/src/mscz.ts
+++ b/src/mscz.ts
@@ -2,9 +2,11 @@
 import { saveAs, assertRes } from './utils'
 import { ScoreInfo } from './scoreinfo'
 
-let msczBufferP: Promise<ArrayBuffer> | undefined
+const MSCZ_BUF_SYM = Symbol('msczBufferP')
 
 export const fetchMscz = async (scoreinfo: ScoreInfo): Promise<ArrayBuffer> => {
+  let msczBufferP = scoreinfo.store.get(MSCZ_BUF_SYM) as Promise<ArrayBuffer> | undefined
+
   if (!msczBufferP) {
     const url = scoreinfo.msczCidUrl
     msczBufferP = (async (): Promise<ArrayBuffer> => {
@@ -16,6 +18,7 @@ export const fetchMscz = async (scoreinfo: ScoreInfo): Promise<ArrayBuffer> => {
       const data = await r.arrayBuffer()
       return data
     })()
+    scoreinfo.store.set(MSCZ_BUF_SYM, msczBufferP)
   }
 
   return msczBufferP
diff --git a/src/scoreinfo.ts b/src/scoreinfo.ts
index 81a1c65..8b105a2 100644
--- a/src/scoreinfo.ts
+++ b/src/scoreinfo.ts
@@ -10,6 +10,8 @@ export abstract class ScoreInfo {
   abstract pageCount: number;
   abstract thumbnailUrl: string;
 
+  public store = new Map<symbol, any>();
+
   get idLastDigit (): number {
     return (+this.id) % RADIX
   }