等待诺言返回未定义？

Question

这是代码：

export const wxreq = (config) => {
config.url = `${HTTP_HOST}${config.url}`;
return new Promise((resolve, reject) => {
    return wepy.request(Object.assign(config, {
        async success (res) {
            // res is a promise, this promise is return  {data: 123}
            const responseFromMiddle = await res;
            return resolve(responseFromMiddle.data);
        },
        fail () {
            reject(new Error(`Request ${config.url} fail!`));
        },
        complete () {
            resolve();
        }
    }))
  })
};

在vuejs生命周期中

async onReady () {
  cosnt res = wxreq(someCorrectConfig);
  console.log(res); // undefined; need to be 123 
}

我很好奇为什么没有定义res？请帮助〜如此困惑！thx〜

Answer 1

实施似乎有问题。 要调用wxreq，您需要在此之前使用await。 还将条件包装在try块中以捕获蚂蚁异常。

async onReady () {
  try {
      const res = await wxreq(someCorrectConfig);
      console.log(res); // undefined; need to be 123 
    }
    catch(err){
    console.log(err)
    }
}

Answer 2

试试这个：在async函数中的异步操作之前使用await

async onReady () {
  const res = await wxreq(someCorrectConfig);
  console.log(res); // undefined; need to be 123 
}

并消除承诺return

export const wxreq = (config) => {
config.url = `${HTTP_HOST}${config.url}`;
return new Promise((resolve, reject) => {
     wepy.request(Object.assign(config, {
        async success (res) {
            // res is a promise, this promise is return  {data: 123}
            const responseFromMiddle = await res;
            return resolve(responseFromMiddle.data);
        },
        fail () {
            reject(new Error(`Request ${config.url} fail!`));
        },
        complete () {
            resolve();
        }
    }))
  })
};

Answer 3

我想你应该做

export async function wxreq(config) {
    const res = await new Promise((resolve, reject) => {
        wepy.request(Object.assign(config, {
            url: `${HTTP_HOST}${config.url}`,
            success: resolve,
            fail: reject
        });
    });
    return res.data;
}

但是在不知道什么是wepy情况下很难说。