我正在尝试建立一种顺序执行诺言的方式。我已经在线上学习了其中一部教程，并提出了以下建议：
function get_data(value){
value = 1
var sheet = SpreadsheetApp.getActiveSheet()
var range = sheet.getRange(1, 1, sheet.getLastRow(), sheet.getLastColumn())
var filter = range.getFilter() || range.createFilter();
var foo_index = 1; // column A
var filterValue = SpreadsheetApp.newFilterCriteria().whenTextEqualTo(value).build()
filter.setColumnFilterCriteria(foo_index, filterValue)
// new code
var data = []
for (var i = 1; i < sheet.getLastRow(); i++) {
if(!sheet.isRowHiddenByFilter(i)) {
var row_data = sheet.getRange(i, 1, 1, sheet.getLastColumn()).getValues()
data.push(row_data[0])
}
}
// end new code
Logger.log(data)
return data
}
但是，有时我会在终端控制台中偶尔收到以下警告：
return promises.reduce((promiseChain, currentTask) => {
return promiseChain.then(chainResults => {
return currentTask.then(currentResult => {
return [ ...chainResults, currentResult ];
}).catch(error => {
errors.push(error);
return;
});
});
}, Promise.resolve([])).then(arrayOfResults => {
console.log("ARRAY_OF_RESULTS", arrayOfResults);
return errors.length > 0 ? response.status(400).send(errors) : response.status(200).send("De advertenties zijn succesvol verstuurd naar alle partner portalen");
});
});
我们如何防止这种情况发生？
如果您需要任何其他信息或需要邀请参加该项目，请随时询问我。我知道可能需要更多信息来进一步调试该问题。
当我更改如下所示的诺言之一时，它不会显示错误。
(node:10894) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 62)
(node:10894) PromiseRejectionHandledWarning: Promise rejection was handled asynchronously (rejection id: 62)
ARRAY_OF_RESULTS undefined
(node:10894) UnhandledPromiseRejectionWarning: #<Object>
(node:10894) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 71)
(node:10894) PromiseRejectionHandledWarning: Promise rejection was handled asynchronously (rejection id: 71)
答案 0 :(得分：1)
问题是您已经立即开始所有动作，并将它们产生的承诺放入promises数组中。这里没有任何东西按顺序运行。你应该写
Promise.allSettled(promises).then(arrayOfResults => {
console.log("ARRAY_OF_RESULTS", arrayOfResults);
const errors = arrayOfResults.filter(res => res.status == "rejected").map(res => res.reason);
if (errors.length > 0)
response.status(400).send(errors);
else
response.status(200).send("De advertenties zijn succesvol verstuurd naar alle partner portalen");
});
如果您确实想按顺序执行动作，则需要在reduce回调的内部中启动每个动作。当前，使用currentTask.then(…)只能按顺序连接解决事件，但是操作是很久以前开始的-当承诺被拒绝时，您可能还没有挂钩，从而导致未处理的拒绝。因此，您需要在该数组中放置一个 task -一个返回promise的函数：
const tasks = []; // an array of functions to be run sequentially
if(autoscoutEnabled) {
tasks.push(() => createAutoscoutAd("/vehicles", jsonAutoscout, "tokenteststring"));
tasks.push(() => addImageToAutoscoutAd("/vehicles/7e59591f-c5a3-974e-e452-2951040ae4ee", file, type, "tokenteststring"));
}
if (marktplaatsEnabled) {
tasks.push(() => createMarktplaatsAd("/advertisements", jsonMarktplaats, "tokenteststring"));
tasks.push(() => addImageToMarktplaatsAd("/advertisements/m1427566569", file, type, "tokenteststring"));
}
return tasks.reduce((promiseChain, currentTask) => {
return promiseChain.then(errors => {
const currentPromise = currentTask();
// this is the important line ^^
return currentPromise.then(() => errors, error => {
errors.push(error);
return errors;
});
});
}, Promise.resolve([])).then(errors => {
console.log("ARRAY_OF_RESULTS", arrayOfResults);
if (errors.length > 0)
response.status(400).send(errors);
else
response.status(200).send("De advertenties zijn succesvol verstuurd naar alle partner portalen");
});
但是，对于顺序执行，我建议使用async / await，它很容易使用。