Mongo/Node: Filtering By Single Properties? - node.js

Question

I am dealing with a query with a criteria object that is being passed as the first argument to this query:
module.exports = (criteria, sortProperty, offset = 0, limit = 20) => {
// write a query that will follow sort, offset, limit options only
// do not worry about criteria yet
console.log(criteria);
const query = Artist.find({ age: { $gte: 19, $lte: 44 } })
.sort({ [sortProperty]: 1 })
.skip(offset)
.limit(limit);
return Promise.all([query, Artist.count]).then(results => {
return {
all: results[0],
count: results[1],
offset: offset,
limit: limit
};
});
};
By default, the criteria object has a single name property that is an empty string.
The age property points to an object that has both min and max values assigned to it. I also have a yearsActive property inside of the criteria object and that also has a min and max value.
So three different properties: age, name and yearsActive.
This has been an extremely challenging one for me and if you look above that's as far as I got.
When my criteria property is console logged it only has a name { name: "" }. It has no yearsActive or age by default when it first starts. So that is where the point of the sliders come in. When I start moving these sliders around on the frontend, then it gets the age and yearsActive appended to the criteria object.
So I need to figure out how to update the query to consider for example the different ages and I have been considering using an if conditional inside a helper function.

Answer 1

Regarding to the comment that I left you.
You have three states at least one when you retrieve the data to the UI. In this case, I would recommend you use aggregation in order to retrieve the data as a model as your business.
For example, the problem as you have is that sometimes you don't know about the max or min value for age or yearsActive, but also you should have an identifier that could be an ObjectId which will be used to update the model identified by that property.
Artist.aggregate([
{
$match: { age: { $gte: 19, $lte: 44 } }
},
{
$sort: { yourProperty: 1 }
},
{
$skip: 10
},
{
$limit: 10
},
{
$project: {
// You set your properties to retrieve with the 1 as flag
propertieX: 1,
"another.property": 1,
"age.max": {
$cond: {
if: { $eq: [ "", "$age.max" ] },
then: 0, // Or the value that you want to set it
else: "$age.max"
}
}
}
}]);
The other state is when you do the query according to the parameters that you're submitting from the form.
If you assurance to retrieve a model with the logic as you want. For example you should return this model in every request using $project and applying the default values when doesn't exist the manipulation in the front-end side as in the searching should be easy to manage.
{
ObjectId: YOUR_OBJECT_ID,
age: {
min: YOUR_MIN_VALUE,
max: YOUR_MAX_VALUE
},
yearsActive: {
min: YOUR_MIN_VALUE,
max: YOUR_MAX_VALUE
}
}
Finally, when you would send the data to save it you should sent the entire model that you returned but the must important thing is identify only that element by the ObjectId to do the update.
NOTE: This is an approach that I will do according with the information that I understand from your question, If I'm bad with me interpretation let me know, and if you want to share more information or open a repository to understand in code, should more easy to me understand the problem.

Answer 2

So what I decided to do since the code would look messy to throw all inside the Artist.find({}) was to create a separate helper function:
const buildQuery = (criteria) => {
console.log(criteria);
};
This helper function is being called with the criteria object and I have to form up the object in such a way that it will represent the query the way in which I want to search the Artist collection.
What made this difficult to wrap my head around was the not very well formed object for searching over a collection with its random properties such as age which has a min and a max which Mongo does not know how to deal with by default. MongoDB does not know what min and max mean exactly.
So inside the helper function I made a separate object to return from this function thats going to represent the actual query that I want to send off to Mongo.
const buildQuery = (criteria) => {
console.log(criteria);
const query = {};
};
I am not modifying the object in anyway, I am just reading some of the desired search results or what the user wants to see from this UI object and so I made this object called query and I added the idea of age.
const buildQuery = (criteria) => {
console.log(criteria);
const query = {};
query.age = {};
};
I decided to do an if conditional inside of the helper function for the specific age range that I want to find.
const buildQuery = (criteria) => {
console.log(criteria);
const query = {};
if (criteria.age) {
query.age = {};
}
};
So this is where the Mongo query operators come into play. The two operators I want to be concerned with is the greater than or equal to ($gte) and the less than or equal to ($lte) operators.
This is how I actually implemented in practice:
const buildQuery = (criteria) => {
console.log(criteria);
const query = {};
if (criteria.age) {
query.age = {
$gte: criteria.age.min,
$lte: criteria.age.max
};
}
};
The query object here will eventually be returned from the buildQuery function:
const buildQuery = (criteria) => {
console.log(criteria);
const query = {};
if (criteria.age) {
query.age = {
$gte: criteria.age.min,
$lte: criteria.age.max
};
}
return query;
};
That query object will be passed off to the find operation:
module.exports = (criteria, sortProperty, offset = 0, limit = 20) => {
// write a query that will follow sort, offset, limit options only
// do not worry about criteria yet
const query = Artist.find(buildQuery(criteria))
.sort({ [sortProperty]: 1 })
.skip(offset)
.limit(limit);
return Promise.all([query, Artist.count]).then(results => {
return {
all: results[0],
count: results[1],
offset: offset,
limit: limit
};
});
};
const buildQuery = (criteria) => {
console.log(criteria);
const query = {};
if (criteria.age) {
query.age = {
$gte: criteria.age.min,
$lte: criteria.age.max
};
}
return query;
};
So what I am doing here is to get the equivalent of Artist.find({ age: { $gte: minAge, $lte: maxAge }).
So for yearsActive I decided to implement something that is nearly identical:
const buildQuery = criteria => {
console.log(criteria);
const query = {};
if (criteria.age) {
query.age = {
$gte: criteria.age.min,
$lte: criteria.age.max
};
}
if (criteria.yearsActive) {
}
return query;
};
So if the user changes the slider, I am going to expect my criteria object to have a yearsActive property defined on it like so:
const buildQuery = criteria => {
console.log(criteria);
const query = {};
if (criteria.age) {
query.age = {
$gte: criteria.age.min,
$lte: criteria.age.max
};
}
if (criteria.yearsActive) {
query.yearsActive = {
$gte: criteria.yearsActive.min,
$lte: criteria.yearsActive.max
}
}
return query;
};