我尝试向对象存储区添加一些值，但在返回时（在第22行）得到以下错误。对象存储区使用keyPath 'id'和自动增量：是的。

function cacheObject(storeName, object) {
  return new Promise(function(resolve, reject) {
    let transaction = db.transaction([storeName], "readwrite");

    transaction.oncomplete = function(event) {
      console.log("Transaction complete");
      resolve(object);
    };

    transaction.onabort = function(event) {
      console.log("Transaction aborted: " + event);
      reject();
    };

    transaction.onerror = function (event) {
      console.log("Transaction error: "+  event.toString());
      reject();
    };

    let objectStore = transaction.objectStore(storeName);

    let objectReq = objectStore.add(object);
    objectReq.onsuccess = function (event) {
      console.log("saved object to idb: " + JSON.stringify(object));
    };
  });
}

以下是onupgradeneeded事件的范例：

req.onupgradeneeded = function (e) {
    let db = e.target.result;
    console.log("Running idb onupgradeneeded");
    if (!db.objectStoreNames.contains(STORY_STORE_NAME)) {
      let storyStore = db.createObjectStore(STORY_STORE_NAME, {keyPath: "id", autoIncrement: true});
      storyStore.createIndex('picture', 'picture', {unique: false});
      storyStore.createIndex('text', 'text', {unique: false});
      //more indexes created here