How to parse HTTP response? - google-apps-script

Question

I'm trying to build a script to run in Google Sheets to automatically pull my bank account balance into the sheet. I'm using Plaid to get the account information. I've pulled the information using UrlFetchApp. I'm stuck trying to figure out how to parse the returned text for the available balance information.
I've tried to use an old XML method to parse it, but quite frankly I don't think I'm even close to figuring out this problem.
function myFunction() {
//HTTP Request
var avail_balance = [];
var data = {
"client_id": "5bf874c39bb5dc0012b1be13",
"secret" : "Redacted",
"access_token" : "Redacted"
};
var payload = JSON.stringify(data);
var options = {
"method" : "POST",
"contentType" : "application/json",
"payload" : payload
};
var url = "https://development.plaid.com/accounts/balance/get";
var response = UrlFetchApp.fetch(url, options);
//Parse HTML
//return avail_balance
return avail_balance
}

Answer 1

The docs for Plaid API say this under API protocols
The Plaid API uses POST requests to communicate and HTTP response
codes to indicate status and errors. All responses come in standard
JSON
Plaid API documentation
You should only use XmlService to parse XML, not JSON. JSON is a standard notation for objects, not just in JavaScript but in many other languages as well so the name is a bit confusing.
Calling UrlFetchApp.fetch() will return an HttpResponse object that you can then parse to JSON (if, in fact, it's a valid JSON - if not, try logging the response first via Logger.log(response))
var responseString = resonse.getContentText();
var data = JSON.parse(responseString);
UrlFetchApp methods

Answer 2

Checked the documentation for the Plaid service and it appears that the response payload is formatted as JSON. So I'm not sure why you'd need to parse the response as HTML.
Try using JSON.parse() on the response instead and then referencing the appropriate property as detailed in the documentation.