1function openIndexedDB() {
 2  let resolve, reject;
 3  const dbPromise = new Promise((res, rej) => {
 4    resolve = res;
 5    reject = rej;
 6  });
 7
 8  const request = window.indexedDB.open("GDUDatabase", 1);
 9
10  request.onerror = function (error) {
11    reject(error);
12  };
13
14  request.onsuccess = function (event) {
15    let db = event.target.result;
16
17    resolve(db);
18
19    db.onerror = function (event) {
20      // Generic error handler for all errors targeted at this database's
21      // requests!
22      console.error("Database error: " + event.target.errorCode);
23    };
24  };
25
26  request.onupgradeneeded = function (event) {
27    const db = event.target.result;
28
29    // 清空旧 objectStore
30    // Array.from(db.objectStoreNames).forEach(name => {
31    //   db.deleteObjectStore(name);
32    // });
33
34    // 创建 objectStore
35    db.createObjectStore("db1", { keyPath: "id" });
36    db.createObjectStore("db2", {
37      keyPath: "id",
38    });
39
40    // 连续创建多个 objectStore 属于同一个 upgrade transaction
41    // https://www.w3.org/TR/IndexedDB/#dom-idbdatabase-createobjectstore
42    request.transaction.oncomplete = function () {
43      const transaction = db.transaction(db.objectStoreNames, "readwrite");
44      const db1ObjectStore = transaction.objectStore("db1");
45      const db2ObjectStore = transaction.objectStore("db2");
46
47      transaction.oncomplete = function () {
48        console.log("add data transaction done!");
49      };
50
51      transaction.onerror = function (error) {
52        console.error(error);
53      };
54
55      // 添加 db1 数据
56      const db1Data = [];
57
58      db1Data.forEach(function (data) {
59        db1ObjectStore.add(data);
60      });
61
62      // 添加 db2 数据
63      const db2Data = [];
64
65      db2Data.forEach(function (data) {
66        db2ObjectStore.add(data);
67      });
68    };
69  };
70
71  return dbPromise;
72}