Tabular Data to Nested JSON - mule-studio

Question

I am trying to convert tabular query output to nested JSON using MuleSoft. My query output is like below:
----------------------------------
Customer | Order | Items
----------------------------------
C | Order1 | Itm1
C | Order1 | Itm2
C | Order2 | Itm1
C | Order2 | Itm4
C | Order3 | Itm3
C | Order3 | Itm4
and using Mule4 dataweave I am trying to convert it in flowing JSON output:
Customer: C
Orders: {
Order1:{
Items: {
Item: Item1
Item: Item2
}
}
Order2:{
Items: {
Item: Item1
Item: Item4
}
}
Order3:
}
So far I have tried code like below with no luck:
%dw 2.0
output application/json
---
payload map ((st, stindex) -> {
Customer: st.Customer,
Orders: payload filter(($.Customer == st.Customer) and ($.Order == st.Order)) map ((f, fIndex) ->{
Order: f.Order
Items : payload filter (($.ItemName == f.ItemName) and ($.Order == f.Order)) map ((i, iIndex) -> {
item: i.ItemName
})
})
})
it seems I am missing something important. Appreciate your help!!

Answer 1

I needed a multilevel groupBy(), mapObjects and a reduce() for the item.
%dw 2.0
output application/json
---
(payload map {
Customer: $.Customer,
Order: $.Order,
Items: $.Items
} groupBy (item) -> item.Customer)
mapObject ((value, key, index) -> {
Customer : key,
Orders: (value groupBy (orders)->orders.Order)
mapObject ((value1, key1, index1) -> {
"$(key1)": value1 reduce ((item, accumulator={}) -> accumulator ++ {Item: item.Items} )
}
)
}
)
Output:
{
"Customer": "C",
"Orders": {
"Order2": {
"Item": "Itm1",
"Item": "Itm4"
},
"Order1": {
"Item": "Itm1",
"Item": "Itm2"
},
"Order3": {
"Item": "Itm3",
"Item": "Itm4"
}
}
}
The indenting of the script is bad but it is too late for me to fix it.