我是否错误地使用了 Promise.all()?

时间:2021-07-26 20:01:25

标签: javascript node.js arrays promise sequelize.js


Code Here
我正在尝试遍历返回响应的迭代,以根据需要准确描述信息。


目前,CaseContactName 和 CaseSiteName 来自不同的 API 调用,然后将数据附加到图表上,但是在当前状态下,响应不会与与表数据相关的内容同步,因为所有这些值都通过模型关系联系在一起。


我希望正确附加联系人姓名和站点名称,我尝试了 3 种不同的循环方法,它要么附加了名字/联系人,要么根本不附加。这是烦躁的数据,有人建议我使用 Promise.All 函数,因为它用于烦躁的情况下,但我觉得我在这里迷路了。
代码如下

       const callRmaCases = async () => {
        //    $tbody.empty(); 
             axios.get('/api/Case').then((response) => {
                for(let i = 0; response.data.length > 0; i++){
                    const caseContactName = Promise.resolve(response.data[i].Contact.name);
                    const caseSiteName = Promise.resolve(response.data[i].Site.siteName);
                     console.log(response);
                     console.log(caseContactName, caseSiteName)
                     
                     Promise.all([caseContactName,caseSiteName]).then((values) => {
                        console.log(values);
                        callRmaInvent([caseContactName,caseSiteName])  
                     });
                };
            }).catch((err) => {
                console.log(err);
            })
            
            };

        const callRmaInvent = async (caseContactName, caseSiteName) => {

        await(caseSiteName, caseContactName);
     axios.get('/api/caseDetail').then((items) => {
        $tbody.empty();
        console.log(items);
        console.log('inventory will go here');
       items.data.forEach((item) => {
            const id = item.id;
            // Table data
            const caseName = item.Case.caseName;
            const caseSite =  caseSiteName;
            const caseContact =  caseContactName;
            const itemType = item.Part.partType;
            const serialNumber = item.Part.serialNumber;
            const createdAt = item.createdAt;
            const updatedAt = item.updatedAt;
            const faultReason = item.Fault.reasonForReturn;
            const dispositionAction = item.Disposition.actionTaken;
            const addedToInvent = dateFns.format(createdAt, 'MMM D, YY')
            const updatedInvent = dateFns.format(updatedAt, 'MMM D, YY')

            $tbody.append(`
            <tr>
            <td>${id}</td>
            <td>${caseName}</td>
            <td>${caseSite}</td>
            <td>${caseContact}</td>
            <td>${serialNumber}</td>
            <td>${itemType}</td>         
            <td>${faultReason}</td>
            <td>${dispositionAction}</td>
            <td>${addedToInvent}</td>
            <td>${updatedInvent}</td>
            </tr>`)
        });
    }).catch((err) => {
        console.log(err)
    });   
    };


您可以看到 Contact 在此处出现未定义一次,但是之后正确显示,我可能只是在这里感到非常困惑并尝试使用错误的方法来实现我需要的结果。
控制台日志显示:

{data: Array(2), status: 200, statusText: "OK", headers: {…}, config: {…}, …}config: {url: "/api/Case", method: "get", headers: {…}, transformRequest: Array(1), transformResponse: Array(1), …}data: (2) [{…}, {…}]headers: {content-length: "1474", content-type: "application/json; charset=utf-8", date: "Mon, 26 Jul 2021 19:47:17 GMT", etag: "W/\"5c2-BNGcGEUTd4sqd6BxFY9mWpUJgeU\"", x-powered-by: "Express"}request: XMLHttpRequest {readyState: 4, timeout: 0, withCredentials: false, upload: XMLHttpRequestUpload, onreadystatechange: ƒ, …}status: 200statusText: "OK"__proto__: Object
script.js:16 Promise {<fulfilled>: "Blake Thompson"}__proto__: Promise[[PromiseState]]: "fulfilled"[[PromiseResult]]: "Blake Thompson" Promise {<fulfilled>: "Disney World"}
script.js:15 {data: Array(2), status: 200, statusText: "OK", headers: {…}, config: {…}, …}config: {url: "/api/Case", method: "get", headers: {…}, transformRequest: Array(1), transformResponse: Array(1), …}data: (2) [{…}, {…}]headers: {content-length: "1474", content-type: "application/json; charset=utf-8", date: "Mon, 26 Jul 2021 19:47:17 GMT", etag: "W/\"5c2-BNGcGEUTd4sqd6BxFY9mWpUJgeU\"", x-powered-by: "Express"}request: XMLHttpRequest {readyState: 4, timeout: 0, withCredentials: false, upload: XMLHttpRequestUpload, onreadystatechange: ƒ, …}status: 200statusText: "OK"__proto__: Object
script.js:16 Promise {<fulfilled>: "Eric"}__proto__: Promise[[PromiseState]]: "fulfilled"[[PromiseResult]]: "Eric" Promise {<fulfilled>: "Warehouse"}
script.js:34 TypeError: Cannot read property 'Contact' of undefined
    at script.js:13
script.js:19 (2) ["Blake Thompson", "Disney World"]0: "Blake Thompson"1: "Disney World"length: 2__proto__: Array(0)
script.js:19 (2) ["Eric", "Warehouse"]

Picture of Table

2 个答案:

答案 0 :(得分:0)

是的,你所做的一切毫无意义。

const caseContactName = Promise.resolve(response.data[i].Contact.name);
const caseSiteName = Promise.resolve(response.data[i].Site.siteName);
                     
Promise.all([caseContactName,caseSiteName]).then((values) => {
  callRmaInvent(caseContactName, caseSiteName)  
});

在此代码示例中,您将 2 个承诺传递给 Promise.all()。 then 处理程序将获得这 2 个承诺的 result,但随后您不会将结果传递给 callRmaInvent,而是传递原始承诺。

相反,你会想要这个:

const caseContactName = Promise.resolve(response.data[i].Contact.name);
const caseSiteName = Promise.resolve(response.data[i].Site.siteName);
                     
Promise.all([caseContactName,caseSiteName]).then((values) => {
  callRmaInvent(values[0], values[1])  
});

但是,这里不需要使用 Promise.resolve(),因为您已经有了数据,因此可以进一步缩短为:

const caseContactName = response.data[i].Contact.name;
const caseSiteName = response.data[i].Site.siteName;
                     
callRmaInvent(caseContactName, caseSiteName)  

整个外层方法可以简化为:

const callRmaCases = async () => {
 
  //    $tbody.empty(); 
  const response = await axios.get('/api/Case');
  for(const item of response.data) {
     const caseContactName = item.Contact.name;
     const caseSiteName = item.Site.siteName;

     callRmaInvent(caseContactName, caseSiteName);
  }
}

答案 1 :(得分:0)

你已经把我认为的一切都做得太过分了。我已经重写了你的代码的一个更简单的版本。可能需要根据服务器的响应进行一些更改。

const callRmaCases = async () => {
try {
    const response = await axios.get('/api/Case')
    // assuming you are getting a json object
    const responseData = await response.json()
    responseData.forEach(innerObject => {
        callRmaInvent(innerObject.Contact.name, innerObject.Site.siteName)  
    })
} catch(error) {
    console.table(error.name, error.type, error.stack)
}  
};

const callRmaInvent = async (caseContactName, caseSiteName) => {
try {
    const items = await axios.get('/api/caseDetail')
    $tbody.empty();
    items.data.forEach((item) => {
            $tbody.append(`
            <tr>
            <td>${item.id}</td>
            <td>${item.Case.caseName}</td>
            <td>${caseSiteName}</td>
            <td>${item.Part.partType}</td>
            <td>${item.Part.serialNumber}</td>
            <td>${item.Part.partType}</td>         
            <td>${item.Fault.reasonForReturn}</td>
            <td>${item.Disposition.actionTaken}</td>
            <td>${dateFns.format(createdAt, 'MMM D, YY')}</td>
            <td>${dateFns.format(updatedAt, 'MMM D, YY')}</td>
            </tr>`)
    });   
} catch(error) {
    console.table([error.name, error.type, error.stack])
}   
};

未解决的承诺可以通过多种方式处理。我喜欢异步等待。