IndexedDBを使おうかと思った、ただ意図的に消さないとずっと残るらしい

IndexedDBを使う

const __debug__ = true;

/**
 * indexedDB操作クラス
 */
class indexDBAccess {
    /**
     * 初期化
     *
     * string dbName DB名
     * string storeName store名
     * int maxDataCount 保存データ数（これを過ぎると古いものから消す）
     */
    constructor(dbName = "indexDbAccess", storeName = 'datas', maxDataCount=1000){
        let self = this;
        if(!indexedDB) {
            self.debuglog("indexedDBが使えない");
            return false;
        }

        self.dbName = dbName;
        self.storeName = storeName;
        self.logMax = maxDataCount;
        self.dbVersion = 1;

        let openReq = indexedDB.open(self.dbName);

        // DBがある場合はバージョンを取得する
        openReq.onsuccess = function(event) {
            let db = event.target.result;
            self.dbVersion = db.version;
            self.debuglog("dbopen success:" + self.dbVersion);
            db.close();
        }

        // DBが無い場合は作成
        openReq.onerror = function(event) {
            self.debuglog("db none");
            self.createDB();
        }
    }

    /**
     * DBとストア作成
     */
    createDB() {
        let self = this;
        self.debuglog("create dbVersion="+self.dbVersion);
        let openReq  = indexedDB.open(self.dbName,self.dbVersion);

        // 新規作成時
        openReq.onupgradeneeded = function(event){
            let db = event.target.result;
            self.dbVersion = db.version;
            self.debuglog("created db upgrade dbVersion="+self.dbVersion);
            let store = db.createObjectStore(self.storeName, {keyPath : 'id', autoIncrement: true});
            db.close();
        }

        // 既に該当のバージョンがある場合
        openReq.onsuccess = function(event){
            let db = event.target.result;
            self.dbVersion = db.version;
            self.debuglog("created db dbVersion="+self.dbVersion);
            db.close();
        }

        // バージョンが上がっている場合エラーになるのでバージョン番号のみ取得する、
        openReq.onerror = function(event) {
            self.debuglog("dbVersion invalid");
            let openReq = indexedDB.open(self.dbName);
            openReq.onsuccess = function(event){
                let db = event.target.result;
                self.dbVersion = db.version;
                self.debuglog("created db dbVersion="+self.dbVersion);
                db.close();
            }
        }
    }

    /**
     * 保存データ数の変更
     * 
     * int maxDataCount 保存データ数
     */
    setMaxCount(maxDataCount=10) {
        this.logMax = maxDataCount;
    }

    /**
     * DBの削除
     */
    drop () {
        if(!indexedDB) {
            return false;
        }
        let self = this;
        let dbName = self.dbName;
        let storeName  = self.storeName;
        self.debuglog("delete count dbVersion="+self.dbVersion);
        self.dbVersion++;
        self.debuglog("delete counted dbVersion="+self.dbVersion);

        indexedDB.deleteDatabase(dbName);
    }

    /**
     * 追加
     */
    add(val) {
        let self = this;
        self.put(val);
    }

    /**
     * 更新
     */
    put(val, key=null) {
        if(!indexedDB) {
            return false;
        }

        let self = this;
        let dbName = self.dbName;
        let storeName  = self.storeName;

        self.debuglog("dbName=" + dbName + " dbViersion=" + self.dbVersion + " write value:" + val);
        let openReq  = indexedDB.open(dbName,self.dbVersion);
    
        openReq.onupgradeneeded = function(event){
            let db = event.target.result;
            self.dbVersion = db.version;
            self.debuglog('write create object store:' + self.dbVersion);
            let store = db.createObjectStore(self.storeName, {keyPath : 'id', autoIncrement: true});
        }

        openReq.onsuccess = function(event){
            let db = event.target.result;
            self.dbVersion = db.version;
            self.debuglog("write db open dbVersion="+self.dbVersion + ":" + db.objectStoreNames.length);
            if (db.objectStoreNames.length<1){
                self.drop();
                self.createDB();
                return;
            }
            let transaction = db.transaction([storeName], "readwrite");
            let store = transaction.objectStore(storeName);
            if (key === null) {
                let result = store.add({value: val});
                self.debuglog("add value");
                result.onsuccess = function(event){
                    let maxkey = event.target.result;
                    self.debuglog("write add dbVersion="+self.dbVersion);
                    if (maxkey>self.logMax) {
                        let keyRangeValue = IDBKeyRange.upperBound(maxkey-self.logMax, false);
                        store.delete(keyRangeValue);
                    }
                }
            }
            else{
                let result = store.put({id: key, value: val});
                result.onsuccess = function(event) {
                    let db = event.target.result;
                    self.dbVersion = db.version;
                    self.debuglog("put value key=" + key + " dbVersion=" + self.dbVersion);
                }
            }
            db.close();
        }
    }

    /**
     * 取得
     */
    dataGet() {
        if(!indexedDB) {
            return false;
        }
        let self = this;

        let resultData = new Array();

        const promise = new Promise((resolve, reject) => {
            let dbName = self.dbName;
            let storeName  = self.storeName;
            let openReq  = indexedDB.open(dbName,self.dbVersion);

            openReq.onupgradeneeded = function(event){
                let db = event.target.result;
                self.dbVersion = db.version;
                self.debuglog('dataGet create object store:' + self.dbVersion);
                let store = db.createObjectStore(self.storeName, {keyPath : 'id', autoIncrement: true});
            }

            openReq.onsuccess = function(event){
                let db = event.target.result;
                self.dbVersion = db.version;
                self.debuglog("dataGet dbVersion="+self.dbVersion);
                if (db.objectStoreNames.length<1){
                    db.close();
                    self.drop();
                    self.createDB();
                    return;
                }
                let transaction = db.transaction([storeName], "readwrite");
                let datas = transaction.objectStore(storeName);

                datas.openCursor().onsuccess = function (event) {
                    let cursor = event.target.result;
                    if (cursor) {
                        let cv = cursor.value;
                        resultData.push(cv);
                        cursor.continue();  
                    }
                }
                db.close();
            }
        });
        return resultData;

    }

    debuglog(msg) {
        if (__debug__) {
            console.log(msg);
        }
    }
}

let db = new indexDBAccess();

function getdata() {
    let result = db.dataGet();
    console.log(result);
}

javascript,indexeddb

2019-03-11 15:07:52

2019-03-12 14:12:33