Javascript callout policy response this error. How can i resolve?

[suchansinee]

this is my js code

var payload = JSON.parse(request.content);
var headers = {'Content-Type' : 'application/json'};
var url = 'https://jsonplaceholder.typicode.com/posts';
var operation = "POST";
var req = new Request(url, operation, headers, payload);
var calloutResponse1 = httpClient.send(req);
context.session['calloutResponse1'] = calloutResponse1;

I use this curl for call proxy

curl -k https://xxxxxx/poc3 -d '{"name": "Apple MacBook Pro 16", "data": "s"}'

this is response error from js callout

{"fault":{"faultstring":"Execution of callapi1 failed on line callapi1_js#5 with error: Unexpected Type. Expected \"String\" got \"NativeObject\"","detail":{"errorcode":"steps.javascript.ScriptExecutionFailedLineNumber"}}}

@dchiesa1 

[dchiesa1]

You’re trying to set a native object into the message context. That won’t work. 

what is your real goal? Why are you attempting to preserve the calloutResponse? 

Also, possibly related: have you considered using the callback approach?  Apigee documentation  recommends it over the callbackResponse approach. 

Using a callback approach, you will not save, examine, or assign the return value of httpClient.send().  You ignore that return value.  

[suchansinee]

my goal is to make asynchronous calls API.

Should I use the js callout policy or the service callout policy?

[dchiesa1]

making multiple asynchronous calls via the JS callout and the httpClient will work.  Use the callback mechanism with httpClient. Search this community site for previous answers for hints.