How to put logic and assert dynamic data using karate - json

Question

Here is my one response for a particular request
{
"data": {
"foo": [{
"total_value":200,
"applied_value": [{
"type": "A",
"id": 79806,
"value": 200
}]
}]
}
}
Here is my another response for the SAME request
{
"data": {
"foo": [{
"total_value":300,
"applied_value": [{
"type": "A",
"id": 79806,
"value": 200
},
{
"type": "B",
"id": 79809,
"value": 100
}
]
}]
}
}
I am unsure for which scenario will I get which response
So the use case is
Whenever there are 2 values in applied_value add two values and assert
Whenever there is only 1 value in applied_value directly assert

Answer 1

Here's one possible solution:
* def adder = function(array) { var total = 0; for (var i = 0; i < array.length; i++) total += array[i]; return total }
* def response =
"""
{
"data": {
"foo": [{
"total_value":300,
"applied_value": [{
"type": "A",
"id": 79806,
"value": 200
},
{
"type": "B",
"id": 79809,
"value": 100
}
]
}]
}
}
"""
* def expected = get[0] response..total_value
* def values = $response..value
* def total = adder(values)
* match expected == total
Just as an example, an alternate way to implement the adder routine is like this:
* def total = 0
* def add = function(x){ karate.set('total', karate.get('total') + x ) }
* eval karate.forEach(values, add)