return Model.create(arr).exec() is not working in mongoose

Question

I heard that exec "returns a promise" so I'm using exec it do asynchronous calls. This question is inspired my other question. The commentator said my code is not working because :

You are using asynchronous code synchronously

I was trying to fix that by using the below code. Don't know if this code will make it not sync but I heard that promises help with that.

so I have this and I cannot create(save) the data but I can delete it. why cant I use the same pattern for create as i did for remove?

var Comp = require("./models/company.js");
  var arr = [
    {name : "comp1",industry : "industry1", ranking: 20},
    {name : "comp2",industry : "industry2", ranking: 5},
    {name : "comp3",industry : "industry3", ranking: 10}
  ]


Comp.find({}).exec()
    .then(function(docs){
        return Comp.remove({}).exec()
        .then(function(){
            console.log("deleted")
        })
    })
    .then(function(){
        return Comp.create(arr).exec()
        .then(function(data){
            console.log(data)
        })
    })

and can you help get to my original goal which was in my other question.

score 4 · Accepted Answer · answered May 18 '16 at 20:51

4

The then funtion does not return promise, the exec does!

So you need to do return Comp.remove({}).exec()

Comp.find({}).exec()
.then(function(docs){
    return Comp.remove({}).exec();
})
.then(function(result_of_remove){
    return Comp.create(arr).exec();
})
.then(function(result_of_create){
    ....
})

answered May 18 '16 at 20:51

Molda

5,619
2
23
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7

Important information. `.create` returns a promise so you shouldn't use `.exec()` http://stackoverflow.com/questions/37358133/trouble-using-promises-with-mongoose .. That's why I got the error. – jack blank May 21 '16 at 02:30

score 2 · Answer 2 · answered May 19 '16 at 02:13

first of all you should confirm you mongoose version.

in older version:

Model.create(doc) returns a query object; call the exec method of the query will trigger the database operation and return a promise.

in new version (i am using 4.4.8) of mongoose Model.create(doc) and 'Model.remove(con)' returns a promise directly.

so check with your version to see if you need to remove some exec

last but not least add catch call to check if you got some errors, it helps when debug

Comp.find({}).exec()
.then(function(docs){
    return Comp.remove({}).exec();
})
.then(function(result_of_remove){
    return Comp.create(arr).exec();
})
.then(function(result_of_create){
    ....
})
.catch(function(error){
  console.log(error)
})

Yup, that was my issue: the .exec() on my create() method was not working. Removed the .exec() and now it returned properly. thank you. — skaz, Jul 30 '19 at 14:23

score 2 · Answer 3 · edited Jun 20 '20 at 09:12

2

I normally use .exec() when I want to return a Promise when working with

Model.findOne(...).exec()

Model.create(...) returns a Promise.

The .exec() function does not exist for Model.create(...)

edited Jun 20 '20 at 09:12

Community

1
1

answered Apr 01 '19 at 00:58

David Ibia

76
2
5

return Model.create(arr).exec() is not working in mongoose

3 Answers3

Model.create(...) returns a Promise.

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