如何访问异步函数 (javascript/react) 中 for-in 循环内的变量？

Question

所以我在 React 项目中创建了这个小的 fetch 函数来循环返回的对象并给我一些东西。
我正在尝试取回 的值profileCount 在异步函数之外访问它。
我该怎么做？

useEffect(() => {
  async function getProfiles() {
    try {
      const url = '';

      let h = new Headers();
      h.append('Accept', 'application/json');

      let encoded = window.btoa('superuser:superuser');
      let auth = 'Basic ' + encoded;

      h.append('Authorization', auth);

      const response = await fetch(url, {
        method: 'GET',
        mode: 'cors',
        headers: h,
        credentials: 'same-origin',
      });
      const data = await response.json();

      let results = data.results;
      let profileCount = 0;

      for (let key in results) {
        let innerObject = results[key];
        for (let newKey in innerObject) {
          if (innerObject[newKey].indexOf('pages/ProfilePage') > -1) {
            profileCount += 1;
            return profileCount;
          }
        }
      }
    } catch (err) {
      console.log('test' + err);
    }
  }
  getProfiles();
}, []);

Answer 1

您的代码很好，只需将 return 语句移到 for 之后。

      for (let key in results) {
        let innerObject = results[key];
        for (let newKey in innerObject) {
          if (innerObject[newKey].indexOf('pages/ProfilePage') > -1) {
            profileCount += 1;
          }
        }
      }

      return profileCount;

工作流程如下，

useEffect(async () => {
  async function getProfiles() {}
  const count = await getProfiles();
}, []);

但您可能必须这样做以避免警告，

    useEffect(() => {
      (async () => {
        let response = await fetch('api/data')
      })();
    }, [])

如何访问异步函数 (javascript/react) 中 for-in 循环内的变量？

How to access variable inside a for-in loop within an async function (javascript/react)?

javascript

fetch

async-await

reactjs