function cancelablePromise() {
    const promise = new Promise(resolve => setTimeout(resolve, 1000))
  
    let cancel: () => void
    const cancelPromise = new Promise((_, reject) => {
      cancel = () => reject("promise canceled")
    })
  
    const wrappedPromise = Promise.race([promise, cancelPromise])
  
    return {
      promise: wrappedPromise,
      cancel: cancel,
    }
  }

The two separate failure channels turn me off. Is this practical or does it introduce unwanted complexity in most cases?

Also wondering what are the Signals that are mentioned.

Kind of reminds me of https://doc.rust-lang.org/rust-by-example/trait/drop.html