YoYo | dead simple comment engine built on top of AWS lambda | Serverless library

As implied in a comment, there are several ways of interpreting the question as originally asked, but the three main interpretations could be realized by adding one of the following to your jq filter:

There's no $regex operator for mongoose. you should insert the regex in the find() query:

Since I haven't noticed you're already using Flask-CORS I'm updating this answer with some further investigations.

I've fired up a testing environment and managed to make this cross-origin request work properly without changing your code. During this process, I came up with the following possible reasons for your issue:

1. Be sure to request an existing tunnel endpoint. Fetching closed NGROK tunnel endpoints result in CORS error, it does not raise a 404. To be sure I'm requesting the correct tunnel I wrote an index view route that just returns success. I also used this endpoint to ensure the CORS was properly set for all HTTP methods (GET, POST...);
2. Be sure to import logging, Flask can lazy evaluate apps and raise exceptions only in request time. Check out your console for tracebacks;
3. In Flask, if an exception occurs during a request, the request handling flow is aborted and Flask-CORS will never be called to add it's headers in the response object, and your browser will always complain about 'Access-Control-Allow-Origin'. That's why you should always check your browser's 'Response Tab', it may contain a traceback or some other useful information;
4. Check for some info in NGROK introspect accessing http://localhost:4040/, it may help you track many issues;
5. I faced some issues running flask-ngrok provided through pip. I've downloaded its source code from GitHub and imported it into my demo app. Frankly, I would ditch this extension and just run $ ngrok http 5000 in another console;
6. Be sure to set FLASK_DEBUG=true or it may hide some info/tracebacks from you.

Check this Gist for the source code I've used and some evidence: https://gist.github.com/magnunleno/8dad91f133a22322250d6cb609792597

If you find any new info or traceback, please let me know so we can work out a solution.

That happens when you run your server under a specific domain (in your case e20e2287e2cb.ngrok.io) but your web client runs in a different domain (suppose www.abcabc.com) and they try to communicate. You should really take a look at this.

This behavior can be configured by managing your app headers Access-Control-* and, luckily, there is a nice extension that does that for you called Flask-CORS.

You could try with

You need a cumulative SUM() function instead of LAG():

demo:db<>fiddle

You can first grab the last index from your array of indexes using .pop(), and then use .reduce() on the now modified indexes array to iterate over your children arrays. By setting the accumulator as the starting htmlDom you can access the objects at each index and its child array for each iteration of .reduce(), where the child array from each object is returned. This child array is then used as the acc for the next call/iteration of your reduce method. Once you have found the last child array, you can use index which you previously popped off your array to set/update the value:

You can use