Get sum of the values of objects in an array

Question

I have a dataweave input as given below.

%dw 2.0
output application/json
var demo = [
    {
        "mat" : 1000,
        "seg" : "z"
    },
    {
        "mat" : 2000,
        "seg" : "b"
    },
    {
        "mat" : 3000,
        "seg" : "x"
    }
]
var count = 0
---
count 

I need the sum of the "mat" field, the count should 6000. How do I achieve this ?

Answer 1

I did it like this

%dw 2.0
output application/json
var demo = [
    {
        "mat" : 1000,
        "seg" : "z"
    },
    {
        "mat" : 2000,
        "seg" : "b"
    },
    {
        "mat" : 3000,
        "seg" : "x"
    }
]
var count = sum(demo.mat)
---
count