headers in preflight response

[jiangen1016]

When I use launchdarkly on my localhost with Angular 6, that is work, but sometimes will tell me net::ERR_INCOMPLETE_CHUNKED_ENCODING 200 (OK). what is this mean?
on my online project, they will tell me error like this
Access to fetch at 'https://clientstream.launchdarkly.com/eval/****' from origin 'https://****' has been blocked by CORS policy: Request header field cache-control is not allowed by Access-Control-Allow-Headers in preflight response. leads:1 GET https://clientstream.launchdarkly.com/eval/**** net::ERR_ABORTED 504 (Gateway Timeout)
What can I do ? Or my network problem？Can I set Request for launchdarkly? Thanks!!!

[eli-darkly]

Thanks for your interest. This sounds like a support ticket that should be directed to our support team here: https://support.launchdarkly.com/hc/en-us/requests/new - they can investigate it and consult with the SDK developers if necessary.

[gavyaggarwal]

I am also getting this issue on version 2.10.2. Looking at the launch darkly source code, it seems like this should be fixed in 2.15.2 with the skipDefaultHeaders flag. Is there an ETA for this release?

[eli-darkly]

@gavyaggarwal I'm not sure what you mean by "an ETA for this release": 2.15.2 was released on 2019-11-15. Also, the skipDefaultHeaders property you're referring to is not part of the JS SDK's API; it is part of the js-eventsource polyfill, and the setting of skipDefaultHeaders in the JS SDK code (which has been there since 2.12.4) simply enables that behavior if you are using that polyfill; other polyfills, and the native EventSource implementation, do not have that option.

Normally, native browser implementations of EventSource do not have this problem. If you are using a polyfill, I would recommend trying the most recent version of js-eventsource. However, I have also seen reports of a similar problem that apparently is not due to EventSource itself but something more specific to Angular... so I would not assume that all similar symptoms have the same cause. Again, I would recommend contacting support to look at your specific circumstances.