Node JS: Promise resolve value is “undefined”
0
I am trying to save multiple documents(via Mongoose) through a recursive method.
I created a Promise which resolves a method admin_save_choices() to save an Array of documents and finally return an Array of Objects after saving the documents or error message. Along with that when a document is saved in callback it recursively call itself(admin_save_choices()) until Array element exists.
Here is the Promise -
let choices_object_array_promise = new Promise(function(resolve, reject) {
let choices_object_array = admin_save_choices(choices, timestamp);
resolve(choices_object_array);
});
choices_object_array_promise.then(function(result){
console.log(result);
res.status(200);
res.json('success');
}).catch(function(error) {
res.status(400);
res.json('error');
});
Here is the method -
var admin_save_choices = function(choices, timestamp) {
let choices_object_array = ;
let choice = choices.shift();
if (typeof choice === "undefined")
return choices_object_array;
let choice_information = {
choice: choice,
created_time: timestamp
};
let save_choice_promise = choiceModel.save_choice(choice_information);
save_choice_promise.then(function(choice_result_object) {
choices_object_array.push(choice_result_object);
admin_save_choices(choices, timestamp);
}).catch(function(error) {
return 'error';
});
}
All documents are being saved successfully except I don't get the result come back to choices_object_array_promise.then( callback.
It is showing undefined in console.log(result)
Thanks in advance.
javascript node.js mongoose
asked Nov 22 '18 at 14:55
user3384985user3384985
1,32721330
add a comment |
0
I am trying to save multiple documents(via Mongoose) through a recursive method.
I created a Promise which resolves a method admin_save_choices() to save an Array of documents and finally return an Array of Objects after saving the documents or error message. Along with that when a document is saved in callback it recursively call itself(admin_save_choices()) until Array element exists.
Here is the Promise -
let choices_object_array_promise = new Promise(function(resolve, reject) {
let choices_object_array = admin_save_choices(choices, timestamp);
resolve(choices_object_array);
});
choices_object_array_promise.then(function(result){
console.log(result);
res.status(200);
res.json('success');
}).catch(function(error) {
res.status(400);
res.json('error');
});
Here is the method -
var admin_save_choices = function(choices, timestamp) {
let choices_object_array = ;
let choice = choices.shift();
if (typeof choice === "undefined")
return choices_object_array;
let choice_information = {
choice: choice,
created_time: timestamp
};
let save_choice_promise = choiceModel.save_choice(choice_information);
save_choice_promise.then(function(choice_result_object) {
choices_object_array.push(choice_result_object);
admin_save_choices(choices, timestamp);
}).catch(function(error) {
return 'error';
});
}
All documents are being saved successfully except I don't get the result come back to choices_object_array_promise.then( callback.
It is showing undefined in console.log(result)
Thanks in advance.
javascript node.js mongoose
asked Nov 22 '18 at 14:55
user3384985user3384985
1,32721330
1
Off-topic. Though this is not directly related to the error. Your code contains a few common Promises Antipatterns. The worst one is "The Collection Kerfuffle" Sequential saving looks like thisconst save = choice=> all => choiceModel.save_choice({choice}).then(item => all.concat(item)); return choices.reduce((saving, item) => saving.then(save(item)), Promise.resolve()
– Yury Tarabanko
Nov 22 '18 at 17:54
add a comment |
0
0
0
I am trying to save multiple documents(via Mongoose) through a recursive method.
I created a Promise which resolves a method admin_save_choices() to save an Array of documents and finally return an Array of Objects after saving the documents or error message. Along with that when a document is saved in callback it recursively call itself(admin_save_choices()) until Array element exists.
Here is the Promise -
let choices_object_array_promise = new Promise(function(resolve, reject) {
let choices_object_array = admin_save_choices(choices, timestamp);
resolve(choices_object_array);
});
choices_object_array_promise.then(function(result){
console.log(result);
res.status(200);
res.json('success');
}).catch(function(error) {
res.status(400);
res.json('error');
});
Here is the method -
var admin_save_choices = function(choices, timestamp) {
let choices_object_array = ;
let choice = choices.shift();
if (typeof choice === "undefined")
return choices_object_array;
let choice_information = {
choice: choice,
created_time: timestamp
};
let save_choice_promise = choiceModel.save_choice(choice_information);
save_choice_promise.then(function(choice_result_object) {
choices_object_array.push(choice_result_object);
admin_save_choices(choices, timestamp);
}).catch(function(error) {
return 'error';
});
}
All documents are being saved successfully except I don't get the result come back to choices_object_array_promise.then( callback.
It is showing undefined in console.log(result)
Thanks in advance.
javascript node.js mongoose
asked Nov 22 '18 at 14:55
user3384985user3384985
1,32721330
I am trying to save multiple documents(via Mongoose) through a recursive method.
I created a Promise which resolves a method admin_save_choices() to save an Array of documents and finally return an Array of Objects after saving the documents or error message. Along with that when a document is saved in callback it recursively call itself(admin_save_choices()) until Array element exists.
Here is the Promise -
let choices_object_array_promise = new Promise(function(resolve, reject) {
let choices_object_array = admin_save_choices(choices, timestamp);
resolve(choices_object_array);
});
choices_object_array_promise.then(function(result){
console.log(result);
res.status(200);
res.json('success');
}).catch(function(error) {
res.status(400);
res.json('error');
});
Here is the method -
var admin_save_choices = function(choices, timestamp) {
let choices_object_array = ;
let choice = choices.shift();
if (typeof choice === "undefined")
return choices_object_array;
let choice_information = {
choice: choice,
created_time: timestamp
};
let save_choice_promise = choiceModel.save_choice(choice_information);
save_choice_promise.then(function(choice_result_object) {
choices_object_array.push(choice_result_object);
admin_save_choices(choices, timestamp);
}).catch(function(error) {
return 'error';
});
}
All documents are being saved successfully except I don't get the result come back to choices_object_array_promise.then( callback.
It is showing undefined in console.log(result)
Thanks in advance.
javascript node.js mongoose
javascript node.js mongoose
asked Nov 22 '18 at 14:55
user3384985user3384985
1,32721330
asked Nov 22 '18 at 14:55
user3384985user3384985
1,32721330
asked Nov 22 '18 at 14:55
user3384985user3384985
1,32721330
asked Nov 22 '18 at 14:55
user3384985user3384985
1,32721330
asked Nov 22 '18 at 14:55
user3384985user3384985
1,32721330
1,32721330
1
Off-topic. Though this is not directly related to the error. Your code contains a few common Promises Antipatterns. The worst one is "The Collection Kerfuffle" Sequential saving looks like thisconst save = choice=> all => choiceModel.save_choice({choice}).then(item => all.concat(item)); return choices.reduce((saving, item) => saving.then(save(item)), Promise.resolve()
– Yury Tarabanko
Nov 22 '18 at 17:54
add a comment |
1
Off-topic. Though this is not directly related to the error. Your code contains a few common Promises Antipatterns. The worst one is "The Collection Kerfuffle" Sequential saving looks like thisconst save = choice=> all => choiceModel.save_choice({choice}).then(item => all.concat(item)); return choices.reduce((saving, item) => saving.then(save(item)), Promise.resolve()
– Yury Tarabanko
Nov 22 '18 at 17:54
1
1
Off-topic. Though this is not directly related to the error. Your code contains a few common Promises Antipatterns. The worst one is "The Collection Kerfuffle" Sequential saving looks like this
const save = choice=> all => choiceModel.save_choice({choice}).then(item => all.concat(item)); return choices.reduce((saving, item) => saving.then(save(item)), Promise.resolve()– Yury Tarabanko
Nov 22 '18 at 17:54
Off-topic. Though this is not directly related to the error. Your code contains a few common Promises Antipatterns. The worst one is "The Collection Kerfuffle" Sequential saving looks like this
const save = choice=> all => choiceModel.save_choice({choice}).then(item => all.concat(item)); return choices.reduce((saving, item) => saving.then(save(item)), Promise.resolve()– Yury Tarabanko
Nov 22 '18 at 17:54
add a comment |
1 Answer
1
active
oldest
votes
2
This is because admin_save_choices do not return anything.
I guess your trying to return the array of admin, maybe this is what you want to do :
// inside admin_save_choices
return save_choice_promise
.then(function(choice_result_object) {
choices_object_array.push(choice_result_object);
return admin_save_choices(choices, timestamp);
}).catch(function(error) {
return error;
});
}
let choices_object_array_fn = new Promise(function(resolve) {
resolve(admin_save_choices(choices, timestamp));
});
Edit: For anti anti-pattern sake :)
answered Nov 22 '18 at 15:02
Fabien GreardFabien Greard
1,2391520
@Paulpro The comment was about a new code in the answer itself. Check the edit history it was like thisnew Promise(async function(resolve, reject)and was corrected (I hope due to my comment :)) BTW I still think it would be great to provide antipattern free solution.
– Yury Tarabanko
Nov 22 '18 at 17:33
@YuryTarabanko Oh, my bad. I did not see the edit history.
– Paulpro
Nov 22 '18 at 17:41
1
BTW I think the code should bereturn admin_save_choices(choices, timestamp);to keep the promise chain :)
– Yury Tarabanko
Nov 22 '18 at 17:45
When pattern matters :)
– Fabien Greard
Nov 22 '18 at 18:20
add a comment |
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1 Answer
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2
This is because admin_save_choices do not return anything.
I guess your trying to return the array of admin, maybe this is what you want to do :
// inside admin_save_choices
return save_choice_promise
.then(function(choice_result_object) {
choices_object_array.push(choice_result_object);
return admin_save_choices(choices, timestamp);
}).catch(function(error) {
return error;
});
}
let choices_object_array_fn = new Promise(function(resolve) {
resolve(admin_save_choices(choices, timestamp));
});
Edit: For anti anti-pattern sake :)
answered Nov 22 '18 at 15:02
Fabien GreardFabien Greard
1,2391520
@Paulpro The comment was about a new code in the answer itself. Check the edit history it was like thisnew Promise(async function(resolve, reject)and was corrected (I hope due to my comment :)) BTW I still think it would be great to provide antipattern free solution.
– Yury Tarabanko
Nov 22 '18 at 17:33
@YuryTarabanko Oh, my bad. I did not see the edit history.
– Paulpro
Nov 22 '18 at 17:41
1
BTW I think the code should bereturn admin_save_choices(choices, timestamp);to keep the promise chain :)
– Yury Tarabanko
Nov 22 '18 at 17:45
When pattern matters :)
– Fabien Greard
Nov 22 '18 at 18:20
add a comment |
2
This is because admin_save_choices do not return anything.
I guess your trying to return the array of admin, maybe this is what you want to do :
// inside admin_save_choices
return save_choice_promise
.then(function(choice_result_object) {
choices_object_array.push(choice_result_object);
return admin_save_choices(choices, timestamp);
}).catch(function(error) {
return error;
});
}
let choices_object_array_fn = new Promise(function(resolve) {
resolve(admin_save_choices(choices, timestamp));
});
Edit: For anti anti-pattern sake :)
answered Nov 22 '18 at 15:02
Fabien GreardFabien Greard
1,2391520
@Paulpro The comment was about a new code in the answer itself. Check the edit history it was like thisnew Promise(async function(resolve, reject)and was corrected (I hope due to my comment :)) BTW I still think it would be great to provide antipattern free solution.
– Yury Tarabanko
Nov 22 '18 at 17:33
@YuryTarabanko Oh, my bad. I did not see the edit history.
– Paulpro
Nov 22 '18 at 17:41
1
BTW I think the code should bereturn admin_save_choices(choices, timestamp);to keep the promise chain :)
– Yury Tarabanko
Nov 22 '18 at 17:45
When pattern matters :)
– Fabien Greard
Nov 22 '18 at 18:20
add a comment |
2
2
2
This is because admin_save_choices do not return anything.
I guess your trying to return the array of admin, maybe this is what you want to do :
// inside admin_save_choices
return save_choice_promise
.then(function(choice_result_object) {
choices_object_array.push(choice_result_object);
return admin_save_choices(choices, timestamp);
}).catch(function(error) {
return error;
});
}
let choices_object_array_fn = new Promise(function(resolve) {
resolve(admin_save_choices(choices, timestamp));
});
Edit: For anti anti-pattern sake :)
answered Nov 22 '18 at 15:02
Fabien GreardFabien Greard
1,2391520
This is because admin_save_choices do not return anything.
I guess your trying to return the array of admin, maybe this is what you want to do :
// inside admin_save_choices
return save_choice_promise
.then(function(choice_result_object) {
choices_object_array.push(choice_result_object);
return admin_save_choices(choices, timestamp);
}).catch(function(error) {
return error;
});
}
let choices_object_array_fn = new Promise(function(resolve) {
resolve(admin_save_choices(choices, timestamp));
});
Edit: For anti anti-pattern sake :)
answered Nov 22 '18 at 15:02
Fabien GreardFabien Greard
1,2391520
edited Nov 22 '18 at 18:20
answered Nov 22 '18 at 15:02
Fabien GreardFabien Greard
1,2391520
answered Nov 22 '18 at 15:02
Fabien GreardFabien Greard
1,2391520
answered Nov 22 '18 at 15:02
Fabien GreardFabien Greard
1,2391520
1,2391520
@Paulpro The comment was about a new code in the answer itself. Check the edit history it was like thisnew Promise(async function(resolve, reject)and was corrected (I hope due to my comment :)) BTW I still think it would be great to provide antipattern free solution.
– Yury Tarabanko
Nov 22 '18 at 17:33
@YuryTarabanko Oh, my bad. I did not see the edit history.
– Paulpro
Nov 22 '18 at 17:41
1
BTW I think the code should bereturn admin_save_choices(choices, timestamp);to keep the promise chain :)
– Yury Tarabanko
Nov 22 '18 at 17:45
When pattern matters :)
– Fabien Greard
Nov 22 '18 at 18:20
add a comment |
@Paulpro The comment was about a new code in the answer itself. Check the edit history it was like thisnew Promise(async function(resolve, reject)and was corrected (I hope due to my comment :)) BTW I still think it would be great to provide antipattern free solution.
– Yury Tarabanko
Nov 22 '18 at 17:33
@YuryTarabanko Oh, my bad. I did not see the edit history.
– Paulpro
Nov 22 '18 at 17:41
1
BTW I think the code should bereturn admin_save_choices(choices, timestamp);to keep the promise chain :)
– Yury Tarabanko
Nov 22 '18 at 17:45
When pattern matters :)
– Fabien Greard
Nov 22 '18 at 18:20
@Paulpro The comment was about a new code in the answer itself. Check the edit history it was like this
new Promise(async function(resolve, reject) and was corrected (I hope due to my comment :)) BTW I still think it would be great to provide antipattern free solution.– Yury Tarabanko
Nov 22 '18 at 17:33
@Paulpro The comment was about a new code in the answer itself. Check the edit history it was like this
new Promise(async function(resolve, reject) and was corrected (I hope due to my comment :)) BTW I still think it would be great to provide antipattern free solution.– Yury Tarabanko
Nov 22 '18 at 17:33
@YuryTarabanko Oh, my bad. I did not see the edit history.
– Paulpro
Nov 22 '18 at 17:41
@YuryTarabanko Oh, my bad. I did not see the edit history.
– Paulpro
Nov 22 '18 at 17:41
1
1
BTW I think the code should be
return admin_save_choices(choices, timestamp); to keep the promise chain :)– Yury Tarabanko
Nov 22 '18 at 17:45
BTW I think the code should be
return admin_save_choices(choices, timestamp); to keep the promise chain :)– Yury Tarabanko
Nov 22 '18 at 17:45
When pattern matters :)
– Fabien Greard
Nov 22 '18 at 18:20
When pattern matters :)
– Fabien Greard
Nov 22 '18 at 18:20
add a comment |
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1
Off-topic. Though this is not directly related to the error. Your code contains a few common Promises Antipatterns. The worst one is "The Collection Kerfuffle" Sequential saving looks like this
const save = choice=> all => choiceModel.save_choice({choice}).then(item => all.concat(item)); return choices.reduce((saving, item) => saving.then(save(item)), Promise.resolve()– Yury Tarabanko
Nov 22 '18 at 17:54