dynamic mongodb query based on user preference in Meteor - mongodb

Question

Based on the logged in user his/her preferences I want to create a collection and display in a view.
I'm in no way experienced with mongodb and now i'm ending up with this huge if/else statement and it's already slow (with 7 users in DB). But afaik it does give me the right results.
Meteor.publish('listprofiles', function () {
if ( ! this.userId ) return [];
var user = Meteor.users.findOne({ _id: this.userId }, {
fields : {
'profile.gender': 1,
'profile.preference': 1
}
}),
query;
user.gender = user.profile.gender;
user.preference = user.profile.preference;
if (user.gender === 'man') {
if (user.preference === 'straight') {
query = {
$and: [
{ 'profile.gender': 'woman' },
{
$or : [{ 'profile.preference' : 'straight' },
{ 'profile.preference' : 'bi' }]
}
]
};
} else if (user.preference === 'gay') {
query = {
$and: [
{ 'profile.gender': 'man' },
{
$or : [{ 'profile.preference' : 'gay' },
{ 'profile.preference' : 'bi' }]
},
]
};
} else if (user.preference === 'bi') {
query = {
$or: [
{
$and: [
{ 'profile.gender': 'man' },
{
$or : [{ 'profile.preference' : 'gay' },
{ 'profile.preference' : 'bi' }]
},
]
},
{
$and: [
{ 'profile.gender': 'woman' },
{
$or : [{ 'profile.preference' : 'straight' },
{ 'profile.preference' : 'bi' }]
}
]
}
]
};
}
The queries work, I tested them, but I'm unsure how to fit them dynamically. My guess is that query also shouldn't be an object, but I'm not sure how to create a valid variable..
var dbFindQuery = Meteor.users.find({
'profile.invisible': false,
queryShouldBeHereButObviouslyThisDoesNotWork
}, {
fields : {
'profile.name': 1,
'profile.city': 1,
'profile.country': 1,
'profile.gender': 1,
'profile.preference': 1,
'profile.story': 1
}
});
console.log(dbFindQuery.fetch());
return dbFindQuery;
anyone can give me a pointer in the right direction?

Answer 1

You can certainly factor out the common query objects. Here's one way to approach it:
Meteor.publish('listprofiles', function() {
if (!this.userId)
return [];
var user = Meteor.users.findOne(this.userId);
var gender = user.profile.gender;
var preference = user.profile.preference;
var straightOrBiWoman = {
'profile.gender': 'woman',
'profile.preference': {$in: ['straight', 'bi']}
};
var gayOrBiMan = {
'profile.gender': 'man',
'profile.preference': {$in: ['gay', 'bi']}
};
var query = {};
if (gender === 'man') {
switch (preference) {
case 'straight':
query = straightOrBiWoman;
break;
case 'gay':
query = gayOrBiMan;
break;
default:
query = {$or: [gayOrBiMan, straightOrBiWoman]};
}
}
query['profile.invisible'] = false;
return Meteor.users.find(query, {fields: {profile: 1}});
});
Here we are reusing straightOrBiWoman and gayOrBiMan based on the user's gender and preference. Note that I used the $in operator to simplify the query. I'd also suggest that you not specify 2nd-level fields in your fields modifier for reasons explained here. Finally, I'd recommend testing this code, as I may have missed something in the logic when rewriting it. Hopefully this example will help guide you in the right direction.