开发者问题收集

我是否错误地使用了 Promise.all()?

2021-07-26
77


代码在此
我试图循环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,但在当前状态下,响应未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绑定。


我希望联系人姓名和站点名称能够正确附加,我尝试了 3 种不同的循环方法,它要么附加名字/联系人,要么根本不附加。这是令人恼火的数据,有人建议我使用 Promise.All 函数,因为它用于令人恼火的情况,但我感觉我在这里迷失了方向。
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)
    });   
    };


你可以看到,Contact在这里出现过一次未定义的情况,但是之后就正确显示了,我可能在这里真的很困惑,并试图使用错误的方法来获得我需要的结果。
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个回答

是的,您所做的没有任何意义。

099346717

在此代码示例中,您将2张承诺将其传递给 Promise.all() 。当时的处理程序将获得这两个承诺的 结果 ,但是您不会将结果传递给 callrmainvent ,您通过了原始承诺。

因此,您需要以下内容:

788178879

但是,这里不需要 Promise.resolve() 数据,因此可以进一步缩短为:

932763207

可以简化整个外部方法:

6044449723
Evert
2021-07-26

我想你把一切都搞得太过了。我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 async-await。

Ritwik Math
2021-07-26