Express api with conditions in query params - node.js

Question

I am working on express Api with mongoose to create get Api for my project. I was able to make one get call successfully. But I am not sure how to make api for sorting data by different fields
Model
id,
productName,
costPrice,
soldPrice
router.get("/sellProduct",
(req, res, next) => {
// condition
if(req.query.product){
Product.find({prodName:req.query.product} ).then(data => {
if (data) {
res.status(200).send(data)
}
})
}
// WHAT SHOULD BE THE SORT LOGIC TO SORT BY DIFF FIELD
else if(req.query.sortBy){
Product.find({}).sort().then(data => {
if (data) {
res.status(200).send(data)
}
})
}
else{
Product.find().then(data => {
if (data) {
res.status(200).send(data)
}
})
}
});
I am beigneer and trying my best but any help will be appreciated

Answer 1

You can build the parameters for .find and .sort dynamically:
router.get("/sellProduct", (req, res, next) => {
const findParams = {};
const sortParams = {
lowerCostPrice: { costPrice: 1 },
higherCostPrice: { costPrice: -1 },
lowerSoldPrice: { soldPrice: 1 },
higherSoldPrice: { soldPrice: -1 },
/* add more sort options ... */
}[req.query.sortBy];
if (req.query.product) findParams.prodName = req.query.product
/* add more search options ... */
Product.find(findParams).sort(sortParams).then(data => {
if (data) {
res.status(200).send(data);
} else {
res.status(404);
}
}).catch(err => {
console.log(err);
res.status(500);
});
});

Answer 2

If I understand you question correctly, you can add a switch block and depending on the passed value, sort the products:
router.get('/sellProduct', (req, res, next) => {
let result;
// ...
if (req.query.sortBy) {
switch (req.query.sortBy) {
case 'lowerCostPrice': {
result = await Product.find({}).sort({ price: 'asc' });
break;
}
case 'higherCostPrice': {
result = await Product.find({}).sort({ price: 'desc' });
break;
}
// and so on...
}
}
// ...
res.status(200).send(result);
});