mongodb find method to display all data if array is empty

Question

Let say I have dynamic array

const branddata = ["adidas", "nike", "puma"]
//this data can be sometime empty too like
// const branddata = []

//now I want to search all the product with brands like

const product = productmodel.find({brand:branddata})

The problem is, this thing works when branddata array is not empty and it gives me the product.

But when it is empty the find method search for a brand which is equal to "" and gives me zero product.

I want all the products to be displayed if branddata is empty.

How can I get this using $regex or any other?

Jatin Parmar · Accepted Answer · 2022-09-01 07:30:31Z

1

you can check branddata is empty or not, and create query object based on it, like this

let q=(branddata && branddata.length>0 )?{brand:branddata}:{};
const product = productmodel.find(q);

when you have multiple params,you can do something like this

let params={
"brand":branddata,
"price":pricedata,
"gender":genderdata
}
let q={};
Object.Keys(params).forEach((t)=>{
if(params[t] && params[t].length>0 ){
    q[t]=params[t]
}
})
const product = productmodel.find(q);

edited Sep 1, 2022 at 7:30

answered Sep 1, 2022 at 6:28

Jatin Parmar

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7 Comments

Yousaf Over a year ago

branddata ? - this won't check if array is empty. You probably meant branddata.length ?

Arman Kazi Over a year ago

Yeah, I got the point. This will work, but what if I have multiple set of array to be check like pricedata=[ ] based upon the fact that users can sometimes make the price filter sometimes don't,

Arman Kazi Over a year ago

Doing this again with all data is not convenient

Jatin Parmar Over a year ago

can you give me list of all params like branddata=>brand,pricedata=>price

Arman Kazi Over a year ago

branddata, pricedata, genderdata=>gender all the array can be empty sometime

|

Arman Kazi · Accepted Answer · 2022-09-01 10:41:41Z

0

Finally found a solution with a function-based approach

$in is used to find document data which are in the array and $nin is used to find document data which are not in the array (basically when array is empty)

const branddata = ["adidas", "nike", "puma"]
const pricedata =["100"]
const genderdata =["male","female"]

const queryfunc = (value)=>{
        var q = {}
        if(value==''){
            q["$nin"]=value;
        }
        else{
            q["$in"]=key;
        }
        return q
 }
 
 const brand=queryfunc(branddata)
 const price=queryfunc(pricedata)
 const gender=queryfunc(genderdata)
    
const product = productmodel.find({brand,price,gender})

answered Sep 1, 2022 at 10:41

Arman Kazi

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