Promise.map没有完成,因为随后的Promise.join首先完成?承诺全部吗? [英] Promise.map not finishing because subsequent Promise.join finishes first? Promise.all?
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问题描述
我仍然信守诺言.
以下是涉及的数据库集合的模型:
Here are the models of the db collections involved:
var itemSchema = new Schema({
label : String,
tag : { "type": Schema.ObjectId, "ref": "tag" }
});
var tagSchema = new Schema({
label : String,
});
这是Promises(地图,地图,地图,联接)的系列:
And here's the series of Promises (map, map, map, join):
现在,Promise.join保存并在"items"图完成运行之前完成,因此"senders"图在保存时不包括"itemsArray" javascriptObject.如何解决此问题?
var reqItems = req.body.items;
var itemsArray = [];
var items = Promise.map(reqItems,function(element){
var existingItem = Models.Item.findOneAsync({ "label": element });
existingItem.then(function (value) {
if ( (existingItem.fulfillmentValue != null) ) { // if this item exists
var itemObject = [
{ "item" : existingItem.fulfillmentValue._id },
{ "label" : existingItem.fulfillmentValue.label }
{ "tag" : existingItem.fulfillmentValue.tag }
];
itemsArray.push(itemObject);
} else { // first instance of this item .. create newItem
var existingTag = Models.Tag.findOneAsync({ "label": element });
existingTag.then(function (value) {
if ( (existingTag.fulfillmentValue != null) ) { // if this tag exists
var newItem = new Models.Item(
{
label : element,
tag : existingTag.fulfillmentValue._id,
}
);
newItem.save(function (err) { // save the newItem with existing tag
console.log(err);
var newSavedItem = Models.Item.findOneAsync({ "label": element });
newSavedItem.then(function (value) { // ensure existence of newItem
var itemObject = [
{ "item" : newSavedItem.fulfillmentValue._id },
{ "label" : newSavedItem.fulfillmentValue.label },
{ "tag" : newSavedItem.fulfillmentValue.tag }
];
itemsArray.push(itemObject); // push item to array
});
});
} else { // else this tag does not exist
var newTag = new Models.Tag(
{
label : element
}
);
newTag.save(function (err) {
console.log(err);
var newSavedTag = Models.Tag.findOneAsync({ "label": element });
newSavedTag.then(function (value) { // ensure existence of newTag
if ( (newSavedTag.fulfillmentValue != null) ) {
var newItem = new Models.Item(
{
label : element,
tag : newSavedTag.fulfillmentValue._id,
}
);
newItem.save(function (err) {
console.log(err);
var newSavedItem = Models.Item.findOneAsync({ "label": element });
newSavedItem.then(function (value) { // ensure existence of newItem
var itemObject = [
{ "item" : newSavedItem.fulfillmentValue._id },
{ "label" : newSavedItem.fulfillmentValue.label },
{ "tag" : newSavedItem.fulfillmentValue.tag }
];
itemsArray.push(itemObject); // push item to array
}); // newSavedItem.then
}); // newItem.save
} // if newSavedTag.isFulfilled
}); // newSavedTag.then
}); // newTag.save
} // else tag does not exist
}); // existingTag.then
} // first instance of this item .. create newItem
}); // existingItem.then
itemObject = null; // reset for map loop
}); // Promise.map itemsArray
var receivers = Promise.map(receiverArray,function(element){
return Promise.props({
username : element
});
});
var senders = Promise.map(senderArray,function(element){
return Promise.props({
username : element,
items : itemsArray
});
});
Promise.join(receivers, senders, function(receivers, senders){
store.receivers = receivers;
store.senders = senders;
var saveFunc = Promise.promisify(store.save, store);
return saveFunc();
}).then(function(saved) {
console.log(saved);
res.json(saved);
})...error handling...});
推荐答案
是的,可以大大简化,尽管您的问题可能只是忘记将任何内容退还给第一个映射器(以及无用的实现价值代码的巨大浪费). /p>
Yes that can be massively simplified, although your problem was probably just forgetting to return anything to the first mapper (and the massive wasteland of useless fulfillmentValue code).
var reqItems = req.body.items;
var items = Promise.map(reqItems, function(element) {
return Models.Item.findOneAsync({ "label": element }).then(function(item) {
if (item != null) {
return item;
} else {
return Models.Tag.findOneAsync({ "label": element }).then(function(tag) {
if (tag == null) {
var newTag = new Models.Tag({label: element});
return newTag.saveAsync().then(function() {
return Models.Tag.findOneAsync({ "label": element });
})
}
return tag;
}).then(function(tag) {
var newItem = new Models.Item({
label: element,
tag: tag._id
});
return newItem.saveAsync().then(function() {
return Models.Item.findOneAsync({ "label": element });
});
})
}
});
});
var receivers = Promise.map(receiverArray, function(element){
return Promise.props({
username : element
});
});
var senders = Promise.map(senderArray, function(element){
return Promise.props({
username : element,
items : itemsArray
});
});
Promise.join(receivers, senders, items, function(receivers, senders, items) {
store.receivers = receivers;
store.senders = senders;
store.items = items;
return store.saveAsync().return(store);
}).then(function(store) {
console.log("saved store", store);
res.json(store);
}).catch(Promise.OperationalError, function(e) {
console.log("error", e);
res.send(500, "error");
});
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