Node.js处理来自链接的promise的响应

我有3个function，每个function都返回一个承诺。 如何将每个承诺的响应分配给定义的对象？

这是我的代码：

const runResponse = { webAudits: [], webJourneys: [], appJourneys: [] }; webAuditsFailures(req) .then( appJourneysFailures(req) ) .then( webJourneysFailures(req) ).then( res.status(201).json({ reports: runResponse }) ); 

这是我试过的：

 webAuditsFailures(req) .then( (response) => { runResponse.webAudits = response }, appJourneysFailures(req) ) .then( (response) => { runResponse.appJourneys = response }, webJourneysFailures(req) ).then( (response) => { runResponse.webJourneys = response }, res.status(201).json({ reports: runResponse }) ); 

但它没有按预期工作，因为webAuditsFailures再次被调用，即使它没有结束，我不明白为什么…

这些是其他失败的尝试来解决这个问题：

使用await

  const webAudits = await webAuditsFailures(req); const appJourneys = await appJourneysFailures(req); const webJourneys = await webJourneysFailures(req); runResponse.webAudits = webAudits; runResponse.webJourneys = webJourneys; runResponse.appJourneys = appJourneys; 

同样的事情发生在这个：

  const webAudits = await webAuditsFailures(req); runResponse.webAudits = webAudits; 

使用co模块：

  co(function* () { var runResponse = yield { webAudits: webAuditsFailures(req), webJourneys: appJourneysFailures(req), appJourneys: webJourneysFailures(req) }; res.status(201).json({ reports: runResponse }); }); 

使用Promise.all ：

 Promise.all([webAuditsFailures(req), appJourneysFailures(req), webJourneysFailures(req)]) .then(function(allData) { res.status(201).json({ reports: allData }); }); 

这是webAuditsFailures函数，它依次调用返回promise的另一个函数

 export default async (req) => { const report = req.body.webAudits; const def = deferred(); if(report.length > 0) { var reportList = []; for(const [reportIndex, item] of report.entries()) { for(const [runIndex, run] of item.runs.entries()) { const result = await waComplianceBusiness(req, run.id); var failureList = []; if(result.data.overviews) { const compliance = result.data.overviews[0].compliance; if(compliance) { for(const [index, rule] of compliance.entries()) { const response = await waRuleOverview(req, run.id, rule.id); const failedConditions = response.data.failedConditions; const ruleName = response.data.ruleName; if(response.data.pagesFailed > 0) { for(const [condIndex, condition] of failedConditions.entries()) { const request = { itemId: condition.conditionResult.id, itemType: condition.conditionResult.idType, parentId: condition.conditionResult.parentId, parentType: condition.conditionResult.parentType } const body = { runId: run.id, ruleId: rule.id, payload: request } waConditionOverview(req, body).done(response => { // do stuff here }); } } } if(failureList.length > 0) { item.runs[runIndex].failures = failureList; } } } } } def.resolve(report); return def.promise } else { return []; } } 

Answer 1

这就是问题：

 waConditionOverview(req, body).done(response => { // do stuff here }); 

您正在执行asynchronous操作，但不会等待结果。 不要使用延迟模型 – 使用util.promisify进行callback。

另外，我强烈build议不要像这样突变请求/请求，而是将信息存储在对象中并返回。

下面是你如何编写代码：

 export default async (req) => { const report = req.body.webAudits; if(report.length === 0) return; const runs = Array.from(report.entries(), ([i, item]) => item.runs.entries()); for (const [_, run] of runs) { const result = await waComplianceBusiness(req, run.id); var failureList = []; if (!result.data.overviews) { continue; } const compliance = result.data.overviews[0].compliance; if(!compliance) { continue; } for(const [_, rule] of compliance.entries()) { const response = await waRuleOverview(req, run.id, rule.id); const { failedConditions, ruleName} = response.data; if(failureList.length > 0) { item.runs[runIndex].failures = failureList; } if(response.data.pagesFailed === 0) continue; for(const [_, condition] of failedConditions.entries()) { const request = { itemId: condition.conditionResult.id, itemType: condition.conditionResult.idType, parentId: condition.conditionResult.parentId, parentType: condition.conditionResult.parentType } const body = { runId: run.id, ruleId: rule.id, payload: request} const reponse = await waConditionOverview(req, body); // do stuff here // update response // update report, so next time we try it's updated and doesn't return empty; } } } return report; } 

Answer 2

在承诺链中，当前的.then()应该返回一个承诺。 这个承诺的结果将被传递给下一个.then() ：

 webAuditsFailures(req) .then((response) => { runResponse.webAudits = response; return appJourneysFailures(req); // return a promise }) .then((response) => { // response contains the result of the promise runResponse.appJourneys = response; return webJourneysFailures(req); }) .then((response) => { runResponse.webJourneys = response; res.status(201).json({ reports: runResponse }); }); 

根据最后.then() .json()中的.then()函数的作用，如果promise链中有其他的.then() ，那么也应该返回。