Mongo + check multiple fields existing - node.js

Question

I am working mongo with nodejs.
I have array list:
var checkFields = ["field1","field2","field3"];
I try to get the count of records having the array list fields and user field is equal to admin.
Sample data:
[
{
"checkFields": {
"field1": "00124b3a5c31",
"user": "admin"
}
},
{
"checkFields": {
"field2": "00124b3a5c31",
"user": "admin"
}
},
{
"checkFields": {
"field1": "00124b3a5c31",
"user": "regular"
}
}
]
Query:
db.collection_name.find(
{"checkFields.user" : "admin"}
{ "checkFields.field1": { $exists: true} }
)
Expected Result:
Result is to get rows of count of matching the field in array list(checkFields).

Answer 1

Building up an $or array for the list of field existence checks is the right approach, but assuming you're on a current node.js build you can simplify the query creation to:
var checkFieldsLists = checkFields.map(field => ({
['checkFields.' + field]: {$exists: true}
}));
var query = {
$or: checkFieldsLists,
'checkFields.user': 'admin'
}
This removes the superfluous $or for the "user is admin" check which lets you also remove the outer $and, so that the generated query is:
{ '$or':
[ { 'checkFields.field1': { '$exists': true } },
{ 'checkFields.field2': { '$exists': true } },
{ 'checkFields.field3': { '$exists': true } } ],
'checkFields.user': 'admin' }

Answer 2

I tried the following code. Its working but don't know its good solution and perfomance. Please anyone have better answer means please post it.
var checkFields = ["field1", "field2", "field3"];
var checkFieldsLists = [];
for ( i = 0; i < checkFields.length; i++) {
var jsObj = {};
jsObj['checkFields.' + checkFields[i]] = {};
jsObj['checkFields.' + checkFields[i]].$exists = true;
checkFieldsLists.push(jsObj);
}
var query = {
"$and" : [{
"$or" : checkFieldsLists
}, {
"$or" : [{
"checkFields.user" : "admin"
}]
}]
};
console.log(JSON.stringify(query));
//console log will return
/*
{"$and":[{
"$or" : [{
"checkFields.field1" : {
"$exists" : true
}
}, {
"checkFields.field2" : {
"$exists" : true
}
}, {
"checkFields.field3" : {
"$exists" : true
}
}]
}, {
"$or" : [{
"checkFields.user" : "admin"
}]
}]
}
*/
collection.find(query);

Answer 3

Here is the solution using aggregate query.
var Db = require('mongodb').Db, Server = require('mongodb').Server, assert = require('assert');
var db = new Db('localhost', new Server('localhost', 27017));
var checkFields = ["field1", "field2", "field3"];
var checkFieldsLists = [];
for (var i = 0; i < checkFields.length; i++) {
var jsObj = {};
jsObj['checkFields.' + checkFields[i]] = {};
jsObj['checkFields.' + checkFields[i]].$exists = true;
checkFieldsLists.push(jsObj);
}
var query = {
"$and" : [{
"$or" : checkFieldsLists
}, {
"$or" : [{
"checkFields.user" : "admin"
}]
}]
};
var matchQuery = {
"$match" : {
"checkFields.user" : "admin",
"$or" : checkFieldsLists
}
};
var groupQuery = {
$group : {
_id : null,
count : {
$sum : 1
}
}
};
var aggregateCheckFields = function(db, callback) {
console.log("Match query is ====>" + JSON.stringify(matchQuery));
console.log("Group query is ====>" + JSON.stringify(matchQuery));
db.collection('checkfields').aggregate([ matchQuery, groupQuery ]).toArray(
function(err, result) {
assert.equal(err, null);
console.log("Result is ===>" + JSON.stringify(result));
if (result.length > 0) {
console.log("Count is ===>" + result[0].count);
}
callback(result);
});
};
db.open(function(err, db) {
aggregateCheckFields(db, function() {
db.close();
});
});
Output:-
Result is ===>[{"_id":null,"count":3}]
Count is ===>3