Memory leak caused due to create too many instances of Api object

[xlc]

Currently every instance of the Api object will create and maintain a web socket connection.
It never disconnects itself and will attempt to reconnect if connection dropped for any reason.

We have an issue that developers are not aware of this behavior and construct a new instance of Api on every method call.
Because the Api object can never automatically GC'ed by JS due to the fact the ws connection is open, this results connection leaks, memory leaks, and unstable application.

I don't know what is the best way to solve this issue other than code review.
I wonder if have polkadot.js enforce shared Api object will help. i.e. have a shared pool of all created api instances, return existing one if parameters (ws url) matches.

[amaury1093]

Yes, I also saw this on 1-2 occasions.

I kind of disagree for a shared singleton pool though, I think we shouldn't fix developers' mistakes with ugly patches (ugly = i don't like singletons). And imo two new Api(...) should always create 2 WS subscriptions.

So I would propose:

• Add this to the docs!
• We could add a singleton pool, but only to show a console.warn() on new new Api(...)

[jacogr]

Marking as docs, not quite open to singleton polls without as specific (switched off by default), flag for this.

[jacogr]

Ok, not sure wtf to add to the documentation here. Where is the current getting started lacking that can be adjusted? (Asking since my first instinct was just to close is)

[xlc]

I guess in this page there can be a section about teardown an instance and mention if you don't teardown it, the instance will live in memory and may not be GC'ed and therefore could cause memory leak.

Or another page about all the thing that developers should be aware of and this will be one of section.