nodeJS mongoose how to make a special get crud - node.js

Question

That's my mongodb data base shown in cmd as you see there is a field named test which exist a time and one other time didn't exist I want to write a get method to find field which contain only imei without test
router.get('/', (req, res, next) => {
Post.find()
.then((posts) => {
res.json(posts);
console.log(posts);
console.log("ok" + JSON.stringify(req.body) + req.body.imei);
})
.catch(err => console.log(err))
});
Here the get method it show me all data base I want to customize it.
{
"_id" : ObjectId("5eb6b927e1c2916320ab28de"),
"imei" : {
"name" : "50"
},
"test" : {
"batterieState" : "0"
},
"__v" : 0
}
{
"_id" : ObjectId("5eb6bbbc09183a3e4c833ebe"),
"imei" : {
"name" : "xx"
},
"__v" : 0
}
{
"_id" : ObjectId("5eb6bbcb09183a3e4c833ebf"),
"imei" : {
"name" : ""
},
"__v" : 0
}
{
"_id" : ObjectId("5eb6bc7809183a3e4c833ec0"),
"imei" : {
"name" : "865566048694354"
},
"__v" : 0
}
{
"_id" : ObjectId("5eb6bcc309183a3e4c833ec1"),
"imei" : {
"name" : "865566048694354"
},
"__v" : 0
}
{
"_id" : ObjectId("5eb6bd1209183a3e4c833ec2"),
"imei" : {
"name" : "865566048694354"
},
"__v" : 0
}
{
"_id" : ObjectId("5eb6bdc609183a3e4c833ec3"),
"imei" : {
"name" : "865566048694354"
},
"__v" : 0
}
{
"_id" : ObjectId("5eb6be4609183a3e4c833ec4"),
"imei" : {
"name" : "xx"
},
"test" : {
"tactileState" : "0",
"pixelState" : "0",
"greyState" : "0"
},
"__v" : 0
}
{
"_id" : ObjectId("5eb6be6609183a3e4c833ec5"),
"imei" : {
"name" : "865566048694354"
},
"__v" : 0
}
{
"_id" : ObjectId("5eb6beef09183a3e4c833ec6"),
"imei" : {
"name" : "xx"
},
"test" : {
"tactileState" : "0",
"pixelState" : "0",
"greyState" : "0"
},
"__v" : 0
}
{
"_id" : ObjectId("5eb6bf8709183a3e4c833ec7"),
"imei" : {
"name" : "865566048694354"
},
"test" : {
"tactileState" : "ignore",
"pixelState" : "ignore",
"greyState" : "ignore"
},
"__v" : 0
}
I want some help for this to write this method correctly to get only fields with imei only and without test.

Answer 1

Use this query
Post.find({
imei: {
$exists: true
},
test: {
$exists: false
}
})
Docs of $exists operator