I don't believe a non-cooperative method exists, either on the JVM or in javascript land. In other words, the code running in your thread must provide support for interruption. However, if you're running in a thread on the jvm, you can also use .interrupt (https://docs.oracle.com/javase/tutorial/essential/concurrency/interrupt.html). Thread .interrupt is supported by some of the java standard library. It can be tricky to get right, but sometimes, it's the right tool.

Right, thank you. But if I use a/thread then I only have a channel, not the thread. I guess inside its body at the very start I could use currentThread and store it somewhere so that an external process can .interrupt it. Likely do it in try … finally and remove it from that place in the finally block so that it is not interrupted when it already is used for other purposes then the a/thread.

I guess trying to interrupt a thread created by a/thread is a bad idea since threads come from a cached thread pool and the thread may have already moved onto another go block.

Depending on if you want to use .interrupt, you could also use your own thread pool that helps support this use case. Using an "interrupt channel" is also a good option in many cases.

Cancelling and interrupting code is always tricky. Maybe the jvm's loom project will help in the future.