javascript - var result = wait someFunc() 返回一个对象，但我期望对象列表

Question

我编写了以下函数来加载indexeddb。 (来自IndexedDB 備忘メモ)我认为这个函数应该返回对象数组。但是，有时它会返回一个对象。 bug的可能性有哪些？Chrome 开发者工具在“加载”函数中表示对象类型为数组。但是，收到“记录”后是对象类型。

    async function load(dbobj, db, index, range) {
      return new Promise(async (resolve, reject) => {
        const saves = [];
        const req = db.transaction(dbobj.storeName).objectStore(dbobj.storeName).index(index).openCursor(range);
        const onfinished = () => {
          console.log(`${saves.length} saves found.`);
          if (saves.length > 0) {
            resolve(saves[saves.length - 1]);
          }
        };
        req.onerror = reject;
        req.onsuccess = (ev) => {
          const cur = ev.target.result;
          if (cur) {
            saves.push(cur.value);
            cur.continue();
          } else {
            onfinished();
          }
        };
      });
    }

    // example of receiving data
    var records = await load(dbobj, db, index, range);

Answer 1

您仅解析最后一个索引处的值!如果需要整个数组，则解析(保存)；

async function load(dbobj, db, index, range) {
      return new Promise(async (resolve, reject) => {
        const saves = [];
        const req = db.transaction(dbobj.storeName).objectStore(dbobj.storeName).index(index).openCursor(range);
        const onfinished = () => {
          console.log(`${saves.length} saves found.`);
          if (saves.length > 0) {
            resolve(saves); // you are resolving only the value at the last index! resolve(saves) if you need the entire array;
          }
        };
        req.onerror = reject;
        req.onsuccess = (ev) => {
          const cur = ev.target.result;
          if (cur) {
            saves.push(cur.value);
            cur.continue();
          } else {
            onfinished();
          }
        };
      });
    }