manipulate data object sequelize ORM (nodejs)

Question

i have code like :

data = await photo.findOne({
    where : {id}
})

that return data

{
     "a" : 2,
     "b" : 5
}

i want to manipulate the data like insert some field

so i add properties :

data.c = data.a * data.b

i check in console.log the data added

{
     "a" : 2,
     "b" : 5,
     "c" " 10
}

but when i return to json

 return res.status(200).json({message: "success", data })

the data still like first { "a" : 2, "b" : 5 }

When you use sequelize, you write to a table. So the first thing is to check the table structure. Do you have a column 'c'? Also how is the ORM schema and how do save the data? — Lorenz Meyer
– Lorenz Meyer, Commented Feb 6, 2018 at 19:04
no i dont have column 'c', but i wanna add some properties "c" to object "data" — Arif Fathurrohman
– Arif Fathurrohman, Commented Feb 6, 2018 at 19:20
I understand now what you are trying to do. I guess your problem is a timing issue. Something with asynchronous code that is not executed in the order you think. — Lorenz Meyer
– Lorenz Meyer, Commented Feb 6, 2018 at 20:04

Bharathvaj Ganesan · Accepted Answer · 2018-02-06 20:06:41Z

6

The reason for your problem is

Finder methods are intended to query data from the database. They do not return plain objects but instead return model instances. Because finder methods return model instances you can call any model instance member on the result as described in the documentation for instances.

When you data.c = data.a * data.b do this, you are basically adding a property to the model instance not to the data object.

You can do something like

dataInstance = await photo.findOne({
    where : {id}
})
data = dataInstance.get({
   plain: true // Important
})
data.c = data.a * data.b;

Cheers. Don't forget to make the answer verified.

answered Feb 6, 2018 at 20:06

Bharathvaj Ganesan

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2 Comments

Arif Fathurrohman Over a year ago

wow i see, i'm misunterstanding for the model, but when i try , why return "dataInstance.get is not a function"

Arif Fathurrohman Over a year ago

the answer is correct, thanks the reason i got error "dataInstance.get is not a function", because the data still in array and i use .findAll()

Sapto Subhan · Accepted Answer · 2019-10-16 04:27:06Z

3

Finally I found answer after searching a lot. you should do something like this

const users = await db.users.findAll({})
.map(el => el.get({ plain: true })) // add this line to code

source :Github issue

answered Oct 16, 2019 at 4:27

Sapto Subhan

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