How to implement conditional statement for the jolt transformation

[Saravanan493556]

This is the input i have:

{

"Consumer": [{
		"id": "fbf814eaae27",
		"singleton": "true"
	}
],
"CoDebtor": [{
		"id": "a452",
		"singleton": true
	}
],
"File": [{
		"id": "bdd99885",
		"singleton": "true"
	}
]
}

[
{
"operation": "shift",
"spec": {
"Consumer": {
"": {
"id": "ConsumerGroup[&1].id",
"singleton": {
"ST": {
"#Stater": "Consumer.[&3].singleton"
},
"HV*": {
"#future": "Consumer.[&3].singleton"
},
"*": {
"singleton": "Consumer.[&3].singleton"
}
}

			}
		}
	}
}

]

Desired output;
If "singleton" Value starts with "ST" output should have "single".
If "singleton" Value starts with "HV" output should have "double".
If "singleton" Value starts with other letters, output should have same words as in input.

[Saravanan493556]

Desired output;
If "singleton" Value starts with "ST" output should have "single".
If "singleton" Value starts with "hv" output should have "double".
If "singleton" Value starts with other letters, output should have same words as in input.