#2314·Recoil

getPromise() in atom effects does not resolve

Author: phjardasCreated Apr 13, 2024Updated Apr 13, 2024

Consider the following scenario where an atom effect tries to get the value of another atom.

javascript
const oneAtom = atom({
  key: "one",
  effects: [
    ({ setSelf }) => {
      setTimeout(() => setSelf("ok"), 1000);
    },
  ],
});

const twoAtom = atom({
  key: "two",
  effects: [
    ({ getPromise, setSelf }) => {
      getPromise(oneAtom)
        .then((value) => setSelf(value))
        .catch((error) => console.error("error in two:", error));
    },
  ],
});

The atom one starts in loading state and only resolves after a second.

I'd expect the promise returned from getPromise(oneAtom) to be initially pending (which it does) and eventually resolve with the value of the atom one when that one resolves. However, the returned promise remains in pending state forever; neither the then nor the catch callback are ever called.

Note that I've intentionally omitted the cleanup logic for setTimeout to keep the example concise.

Source: facebookexperimental/Recoil