如何等待异步函数中的获取响应？

leabum 发表于 Dev

LeaBS

如果我在控制台中查看，它将给我：

coursesbody is: 
Promise { "pending" }

<state>: "pending"

const fetchCourses = async args => {
    await fetch(`/coursemanagement/getschoolcourse`, {
      method: "POST",
      body: JSON.stringify({ schoolId: currentSchool2 }),
      headers: {
        "Content-Type": "application/json"
      }
    }).then(res =>{
      const body = res.json();
      console.log("coursesbody is:", body)
      return res.json()
    })
  };

等待响应的正确方法是什么？我很难在js中将头缠在await / async上。

编辑：在useEffect我现在打电话

useEffect(() => {
    setSchoolsCoursesDocents()
}

setSchoolsCoursesDocents（）为：

 const setSchoolsCoursesDocents = async () => {
    const schools= await fetchSchools();
    const courses = await fetchCourses(schools);
    const docents = await fetchDocents(courses);
  };

fetchSchools看起来像：

const fetchSchools = async () => {
    const result = await fetch(`/coursemanagement/getschools`, {
      method: "GET"
    });
    const body = await result.json();
    setSchools(body);
    setCurrentSchool1(body[0].id)
    setCurrentSchool2(body[0].id)
  };

然后在以下情况中使用状态currentSchool2：

 const fetchCourses = async args => {
    console.log("currentSchool2 is", currentSchool2)
    const result = await fetch(`/coursemanagement/getschoolcourse`, {
      method: "POST",
      body: JSON.stringify({ schoolId: currentSchool2 }),
      headers: {
        "Content-Type": "application/json"
      }
    });
    const body = await result.json();
    setCourses(body);
    setCurrentCourse(body[0].courseId);
  };

但是console.log是未定义的，但是应该在第一次获取时将currentSchool2设置为1。

佐伊卜·伊亚兹（Zohaib Ijaz）

这是异步等待的方式

const fetchCourses = async args => {
    const res = await fetch(`/coursemanagement/getschoolcourse`, {
      method: "POST",
      body: JSON.stringify({ schoolId: currentSchool2 }),
      headers: {
        "Content-Type": "application/json"
      }
    });
    const body = await res.json();
    console.log("coursesbody is:", body)
    return body;
  };

  // here is how you call this function
  const data = await fetchCourses();

// If you have multiple functions and data from one function is being used in second and so on then you can do something like
  const schools= await getSchools();
  const courses = await getCourses(schools);
  const docents = await fetchDocents(courses);

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