Added access to Worker's terminate method when run through comlink-loaded

[aelgasser]

When workers are loaded through comlink-loader there is no way to access the underlying Worker object through the proxy returned by comlink-loader and terminate it.

This patch maps a terminate method on the proxy to the worker's terminate method.

proxy[Comlink.releaseProxy]()is not enough in the case of Web Workers as the worker is not terminated only its endpoint if any is closed.

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[aelgasser]

@googlebot I fixed it.

[aelgasser]

@googlebot I fixed it.

[aelgasser]

@googlebot I fixed it.

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[surma]

A proxy doesn’t necessary sit on top of a Worker. It is often just wrapping a MessagePort and therefore has no knowledge of the Worker. In some scenarios, Comlink is used without a Worker being involved at all (e.g. in the iframe use-case). Additionally, apart from terminate() sometimes not existing und the underlying, wrapped primitive, there are often multiple proxies from the same worker, and being able to call terminate() on one of the proxies would leave the other proxies in a dysfunctional state.

I think your desire to get access to the worker is valid, but should be a bug on comlink-loader, rather than here.

I’m closing this, but feel free to re-open if you disagree.

[aelgasser]

It makes sense and I was thinking, too, it should be in comlink-loader. And rethinking about it and the code I put, it's also adding an unnecessary dependancy on Worker.

I'm going to submit a pull request to comlink-loader then to solve the issue.

[aelgasser]

@surma here is the pr GoogleChromeLabs/comlink-loader#27