How to reiterate json response to extract a token and to make a restapi call with for-each activity - rest

Question

i am using Copy Data activity(Can't use Web activity due to security reasons) to connect to Rest API(source) (via REST dataset)and I get a response in json format as shown below which is what i need, only that this is the first page and there are many other pages that i need to retrieve. The retrieved information is then saved in SQL database table (destination). In process to retrieve the next pages i need to extract the token from "continuationToken" and send it back to my REST dataset as an dynamic value. Not sure if this is the correct way but gave it a try.
[
{
"pagedResponse":[
{
"docType":"current",
"orgNumber":"98789765",
"persons":[
],
"clientId":43533,
"name":null,
"clientResponsible":{
"id":null,
"name":null
}
}
],
"continuationToken":{
"token":"-RID:Om1+ANeDbNMWASEAAAAAAAAA==#RT:1#TRC:10#ISrV:2#IEO:6554436",
"range":{
"min":"",
"max":"05C1DFFFFFFFFFFC"
}
}
}
]
I tried to run some test by saving the json response as a file. Created Lookup activity(Lookup1) to read in the json file and in the then created a for-each activity and in the items i added a dynamic content
#activity('Lookup1').output.value[0].continuationToken
but got this error message.:
{
"errorCode": "InvalidTemplate",
"message": "The function 'length' expects its parameter to be an
array or a string. The provided value is of type 'Object'.",
"failureType": "UserError",
"target": "ForEach1"
}
expected result was:
"token":"-RID:Om1+ANeDbNMWASEAAAAAAAAA==#RT:1#TRC:10#ISrV:2#IEO:6554436",
"range":{"min":"","max":"05C1DFFFFFFFFFFC"}

Answer 1

I think your solution mentioned in the question should work.I suppose that you want to know whether the continuationToken is null so that the loop should be ended,so you use length function.However,according to the error message:The function 'length' expects its parameter to be an array or a string. The provided value is of type 'Object'. It is stated in the document clearly:
Then continuationToken is an object,should be used with empty function: