问题[indexeddb]

   
class IndexedDb {

    constructor() {
        var self = this;
  

        var indexedDB = window.indexedDB || window.mozIndexedDB || window.webkitIndexedDB || window.msIndexedDB || window.shimIndexedDB;

        if (!indexedDB) {
            return;
        }

        var open = indexedDB.open(db, 2);

        open.onupgradeneeded = function() {
            ...
        };

        open.onerror = function(event) {
            ...
        };

        open.onsuccess = function(event) {
            debugger;
            console.log("onsuccess")
            ...
        }


    }
}

if(!Indexeddb) {
var Indexeddb = new IndexedDb();
}

export default Indexeddb;