Validate JSON response with array values - json

Question

I have a JSON response as shown below (in array values). I want to validate whether the Keys (attributes) are properly retrieved in the Response. I would like to compare a list of expected values against the response values (only the first set of array values)
Eg:
"participants": [
{
"FirstName": "Kim",
"LastName": "Hykes",
"Street1": "ABC",
"Street2": "ABCD",
"City": "city1",
"State": "NJ"
}
{
"FirstName": "John",
"LastName": "David",
"Street1": "XYZ",
"Street2": "UXYZ",
"City": "city2",
"State": "NY"
}
]
Using JSONparser, the above JSON is parsed and the result will be:
participants[0].FirstName, participants[0].LastName,
participants[0].Street1, participants[0].Street2, participants[0].City,
participants[0].State, participants[1].FirstName,
participants[1].LastName,
participants[1].Street1, participants[1].Street2, participants[1].City,
participants[1].State
And it goes on until 50 participants
I would like to see whether all the required Keys are fetched from the database and would like to check only the first Array fields i.e. only in Participants[0].
Can anyone help me to figure the solution here?

Answer 1

Do you mean something like this, to validate whether the keys are in there, and in the correct order?
var response = {"participants": [
{
"FirstName": "Kim",
"LastName": "Hykes",
"Street1": "ABC",
"Street2": "ABCD",
"City": "city1",
"State": "NJ"
},
{
"FirstName": "John",
"LastName": "David",
"Street1": "XYZ",
"Street2": "UXYZ",
"City": "city2",
"State": "NY"
}
]
}
var keysNeeded = ['FirstName', 'LastName', 'Street1', 'Street2', 'City', 'State']
var i = 0;
for (key in response.participants[0]) {
if (key == keysNeeded[i]) {
console.log('all is OK with key '+key)
}
i++;
}