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pcthrowaway 2 hours ago

In the repeater callback, you're both calling the stop argument and awaiting it. Is it somehow both a function and a promise? Is this possible in JS?

edit: I found where stop is created[1]. I can't say I've seen this pattern before, and the traditionalist in me wants to dislike the API for contradicting conventions, but I'm wondering if this was designed carefully for ergonomic benefits that outweigh the cost of violating conventions. Or if this was just toy code to try out new patterns, which is totally legit also

[1]: https://github.com/repeaterjs/repeater/blob/638a53f2729f5197...

bikeshaving 2 hours ago | parent [-]

Yes, the callable promise abstraction is just a bit of effort:

  let resolveRef;
  const promise = new Promise((res) => { resolveRef = res; });
  
  const callback = (data) => {
    // Do work...
    resolveRef(data); // This "triggers" the await
  };

  Object.assign(callback, promise);

There’s a real performance cost to awaiting a fake Promise though, like `await regularPromise` bypasses the actual thenable stuff.