Question

我得到一个args数组作为参数，然后我根据下面的算法进行了大量的服务器调用。

将args数组作为数据发布到endpoint / abc。
迭代args数组，

一个。一次拉3并发送3次调用到端点/ pqr

湾一旦3个电话进入步骤＆＃39; 2.a＆＃39;成功发送3个Post调用到endpoint / def

℃。收集步骤＆＃39; 2.a＆＃39;服务器调用并将其推入数组。

d。重复步骤a，b，c直到args长度。

下面给出了整个过程的代码片段，执行从函数execute（args）开始。

import Promise from 'bluebird';

import request from 'superagent';

// sends a post request to server 
const servercall2 = (args, response) => {

        const req = request
            .post(`${baseUrl}/def`)
            .send(args, response)
            .setAuthHeaders();

        return req.endAsync();
};

// sends a post request to server
const servercall1 = (args) => {

        const req = request
            .post(`${baseUrl}/abc`)
            .send(args)
            .setAuthHeaders();

        return req.endAsync()
            .then((res) => resolve({res}))
            .catch((err) => reject(err));
};

async function makeServerCalls(args, length) {

    // convert args to two dimensional array, chunks of given length [[1,2,3], [4,5,6,], [7,8]]

    const batchedArgs = args.reduce((rows, key, index) => (index % length === 0 ? rows.push([key])
        : rows[rows.length - 1].push(key)) && rows, []);

    const responses = [];

    for (const batchArgs of batchedArgs) {
        responses.push(
            // wait for a chunk to complete, before firing the next chunk of calls
            await Promise.all(

                ***// Error, expected to return a value in arrow function???***
                batchArgs.map((args) => {
                    const req = request
                        .get(`${baseUrl}/pqr`)
                        .query(args)

                    // I want to collect response from above req at the end of all calls.
                    return req.endAsync()
                        .then((response) =>servercall2(args,response)); 
                })
            )
        );
    }

    // wait for all calls to finish
    return Promise.all(responses);
}

export function execute(args) {
    return (dispatch) => {

       servercall1(args)
           .then(makeServerCalls(args, 3))
           .then((responses) => {
                    const serverresponses = [].concat(...responses);
                    console.log(serverresponses);
            });
    };
}

我面临几个问题

2.c似乎没有正常工作＆＃34;收集步骤＆＃39; 2.a＆＃39;服务器调用并将其推入数组。＆＃34;。错误：希望在箭头函数中返回一个值。我在这做错了什么？请注意，最后我只关心步骤2.a的响应。
这是一个正确的链接还是可以根据上述要求进行优化？
我必须做其他任何失败处理吗？

Answer 1

可能是这样 - batchArgs.map中的每个项目都应该是Promise我认为？然后Promise.all将等待每个完成：

batchArgs.map((args) => {
    const req = request
        .get(`${baseUrl}/pqr`)
        .query(args)


    // Return promise here
    return req.endAsync()
        .then((response) =>servercall2(args,response))
        .then((res) => res);
})

Answer 2

你有一段文字砖，所以它有点难以破译你实际想要实现的目标，但我会给出我给出的代码两分钱。

 //Both server calls can be simplified.. no need to
 //wrap in another promise if one is being returned
 const servercall2 = (args, response) => {
       const req = request
            .post(`${baseUrl}/def`)
            .send(args, response)
            .setAuthHeaders();

        return req.endAsync();
};

    //Here... you return no value in the function passed to map, thus an 
    //error is being thrown. You need to return a Promise from here so that
    //it can be passed into Promise.all

        const allFinished = await Promise.all(
        batchArgs.map((args) => {
            const req = request
                .get(`${baseUrl}/pqr`)
                .query(args)

            // I want to collect response from above req at the end of all calls.
            return req.endAsync()
        })
       );
       allFinished.then(function(results){

       });

有条件的承诺链

2 个答案: