yield resolves to yielded value

[mbostock]

Currently yield 42 resolves to undefined. Now it resolves to the yielded value, 42. In the case a promise is yielded, it resolves to the resolved promise value, similar to await. This makes it easier e.g. to create a map with Leaflet. Instead of:

viewof map = {
  const container = htl.html`<div style="height:600px;">`;
  yield container;
  const map = container.value = new mapboxgl.Map({
    container,
    center: [-77.033485, 38.897205],
    zoom: 10,
    style: "mapbox://styles/mapbox/streets-v11",
    scrollZoom: false
  });
  invalidation.then(() => map.remove());
}

You can now say:

viewof map = {
  const container = yield htl.html`<div style="height:600px;">`;
  const map = container.value = new mapboxgl.Map({
    container,
    center: [-77.033485, 38.897205],
    zoom: 10,
    style: "mapbox://styles/mapbox/streets-v11",
    scrollZoom: false
  });
  invalidation.then(() => map.remove());
}

[visnup]

There's no possible way for the user to get the underlying generator for a cell with a yield, right? If so, that could open up a method to send information back to the yield from outside.

[mbostock]

There's no possible way for the user to get the underlying generator for a cell with a yield, right?

No, not unless we introduce a new operator like generatorof, but I’m not even sure how that would work because only one thing can be responsible for running the generator. So, I think it’s unlikely we’d ever want yield to return something else.

[Fil]

I got @visnup to explain that to me and … 🤯 !