How to use JSONiq for JSON

The question is to write a JSONiq FLWOR expression that can display the name of the products which their price are at least 3.

I have tried the answers provided on How to run JSONiq from JSON with try.zorba.io but that's not the answers that i expect. Beside that, I also tried a lot of JSON FLWOR expression but still getting errors in try.zobia.io. This is my JSON file.

{
    "supermarket": {
        "visit": [ {
            "_type": "bought", 
            "date": "March 8th, 2019",
            "product": [ {
                    "name": "Kit Kat",
                    "amount": 3,
                    "cost": 3.5
                    },
                {
                    "name": "Coca Cola",
                    "amount": 2,
                    "cost": 3
                    },
                {
                    "name": "Apple",
                    "amount": "Some",
                    "cost": 5.9
                    }
                ]
            },  
            {
            "_type": "planning", 
            "product": [{
                    "name": "Pen",
                    "amount": 2
                    },
                {
                    "name": "Paper",
                    "amount": "One ream"
                    }
                ]
            }
        ]
    }
}

This is my current JSONiq expression.

jsoniq version "1.0";
let $a := { (: my JSON file :) }    
for $x in $a.supermarket.visit
let $y = $x.product()
where $y.price >= "3.0"
return $y.name

The final output should be Kit Kat, Coca Cola and Apple. I would appreciate some helps for my JSON file or JSONiq.

Solution

visit also is an array, so you need the parenthesis to get to the individual visits in the for. This

jsoniq version "1.0";
let $data := { (: my JSON file :) }
for $visit in $data.supermarket.visit()
for $product in $visit.product()
where $product.cost ge 3
return $product.name

would return

Kit Kat Coca Cola Apple

Since the above produces a sequence, you can use it anywhere where sequences are allowed.

let $data := { (: my JSON file :) }
return string-join(
  for $visit in $data.supermarket.visit()
  for $product in $visit.product()
  where $product.cost ge 3
  return $product.name
, ", ")

Result:

Kit Kat, Coca Cola, Apple

Of course this would work as well:

for $product in $data.supermarket.visit().product()
where $product.cost ge 3
return $product.name