Response object is not defined when passed in a function - node.js

Question

I am using Facebook Graph NodeJS API to fetch user_posts. The response has pagination and therefore I need to loop over the response to fetch all the posts. I am using following route to fetch facebook posts and I am looping over pagination using get_user_statuses function:
var posts = "";
function get_user_statuses(response_posts, res) {
var link_regex = /https?:\/\/(?:www\.|(?!www))[^\s\.]+\.[^\s]{2,}|www\.[^\s]+\.[^\s]{2,}/g;
var isNextPageAvailable = true;
if ("paging" in response_posts) {
var nextPage = response_posts.paging.next;
isNextPageAvailable = true;
} else {
isNextPageAvailable = false;
}
for (var i = 0; i < response_posts.data.length; i++) {
var post = response_posts.data[i].message + " ";
if ("message" in response_posts.data[i]) {
posts += post.replace(link_regex, "");
}
}
if (nextPage !== undefined) {
request(nextPage, function (error, response, body) {
if (!error && response.statusCode === 200) {
get_user_statuses(JSON.parse(body));
} else {
console.log(error);
}
});
}
if (!isNextPageAvailable){
//Sending posts to facebook Modal
console.log(posts);
res.send(JSON.stringify({posts: posts})); //res is not defined here
}
}
router.post('/fbData', function (req, response, next) {
FB.setAccessToken(req.body.access_token);
FB.api('/me?fields=posts&posts.limit=1000', function (res) {
if (!res || res.error) {
if (!res) {
response.send(JSON.stringify({error: 'An error occurred. Please try again.'}))
}
response.send(JSON.stringify({error: response.error}));
return;
}
get_user_statuses(res.posts, response); //Passing response object here
});
});
The issue is that response object passed from express route is not defined in get_user_statuses function. Now I have two question:
Why is response object is not defined?
Is there better approach to achieve this arrangement?

Answer 1

res is not defined because you forgot to pass it in internal call. Change get_user_statuses(JSON.parse(body)); to get_user_statuses(JSON.parse(body), res); and it should work

Answer 2

I solved my problem. I needed to create a function with a callback. In case anyone else is stuck at this kind of issue, this post helped me resolve it:
[How to recurse asynchronously over API callbacks in node.js?