Add the ability to abort an initial connection attempt

[ethanlookpotts]

I discovered this while working with an offline robot - if you're making your initial connection with retries, there was previously no ability to abort the reconnect attempts once they started. This allows the user to pass in an object with the rest of the dial options that they can later cancel.

Change log

• Add reconnectAbort option to DialOpts
• Do not retry if reconnectAbort.abort is true
• Update vanilla example with usage

Tested

• Vanilla example
• Used in app, observed behavior is resolved!

[njooma]

A couple of questions:

1. Why does it have to be an object? Can it not just be a boolean? Does it have something to do with reference semantics if it's an object?
2. The connection logic returns a promise, right? Is there a way to have the cancellation of the promise work as the abort signal?

[ethanlookpotts]

1. Why does it have to be an object? Can it not just be a boolean? Does it have something to do with reference semantics if it's an object?

Exactly, we want the reference semantics of the object so that the connection can be cancelled later. Initially, the caller would set reconnectAbort.abort to false and then later decide to stop attempting reconnects and set to true.

2. The connection logic returns a promise, right? Is there a way to have the cancellation of the promise work as the abort signal?

Unfortunately promises don't support cancel natively. The closest thing is you can use an AbortController with fetch but that doesn't help us with this vanilla promise - we would have to manually listen to the signal just like we're doing here.

[njooma]

@ethanlook Ok cool thanks for clarifying! Can we call it something like reconnectCancelSignal or reconnectAbortSignal or something? So that it's clear that setting the value will actually signal to the connection client that it should abort? Unless that goes against a TS naming convention

[ethanlookpotts]

@njooma Happy to change the name! I chose this one because it matches the exponential-backoff parameter. reconnectAbortSignal sounds good to me!

[ethanlookpotts]

@njooma renamed to reconnectAbortSignal: c8d93fb