jotai-eager/dist/index.mjs

Jōtai utilities that help with asynchronous atoms

import { atom } from 'jotai/vanilla';

const PENDING = { status: "pending" };
const promiseMetaCache = /* @__PURE__ */ new WeakMap();
function isPromiseLike(value) {
  return typeof value?.then === "function";
}
function getPromiseMeta(promise) {
  if (!isPromiseLike(promise)) {
    return void 0;
  }
  return promiseMetaCache.get(promise) ?? PENDING;
}
function setPromiseMeta(promise, meta) {
  promiseMetaCache.set(promise, meta);
}
function isKnown(value) {
  const meta = getPromiseMeta(value);
  if (meta) {
    return meta.status === "fulfilled";
  }
  return true;
}
function getFulfilledValue(promiseOrValue) {
  const meta = getPromiseMeta(promiseOrValue);
  if (meta) {
    return meta.value;
  }
  return promiseOrValue;
}

function soon(first, second) {
  if (second) {
    return _soonImpl(first, second);
  }
  return (data) => {
    return _soonImpl(data, first);
  };
}
function _soonImpl(data, process) {
  const meta = getPromiseMeta(data);
  if (meta) {
    if (meta.status === "fulfilled") {
      return process(meta.value);
    }
    if (meta.status === "rejected") {
      return Promise.reject(meta.reason);
    }
    const promise = data;
    const transformedPromise = promise.then(
      (value) => {
        setPromiseMeta(promise, { status: "fulfilled", value });
        return process(value);
      },
      (reason) => {
        setPromiseMeta(promise, { status: "rejected", reason });
        throw reason;
      }
    );
    return transformedPromise;
  }
  try {
    return process(data);
  } catch (err) {
    return Promise.reject(err);
  }
}

function soonAll(values) {
  if (values.every(isKnown)) {
    return values.map((el) => getFulfilledValue(el));
  }
  return Promise.all(values).then((fulfilledValues) => {
    fulfilledValues.map((fulfilled, idx) => {
      const promise = values[idx];
      if (isPromiseLike(promise)) {
        setPromiseMeta(promise, { status: "fulfilled", value: fulfilled });
      }
    });
    return fulfilledValues;
  });
}

function derive(deps, op) {
  return atom((get) => {
    try {
      return soon(
        soonAll(deps.map(get)),
        (values) => op(...values)
      );
    } catch (err) {
      return Promise.reject(err);
    }
  });
}

const NotYet = Symbol(
  "(jotai-eager) Not all dependencies were fulfilled. Are you a dev? Call `isEagerError(e)` to detect this thrown value and rethrow it, as its handled by the library."
);
function unwrapPromise(promise) {
  const meta = getPromiseMeta(promise);
  if (!meta) {
    return promise;
  }
  if (meta.status === "pending") {
    throw { [NotYet]: promise };
  }
  if (meta.status === "rejected") {
    throw meta.reason;
  }
  return meta.value;
}
function resolveSuspension(compute, signal) {
  try {
    return compute();
  } catch (e) {
    const suspended = e[NotYet];
    if (suspended) {
      return suspended.then(
        (value) => {
          setPromiseMeta(suspended, { status: "fulfilled", value });
          if (signal.aborted) {
            return void 0;
          }
          return resolveSuspension(compute, signal);
        },
        (reason) => {
          if (signal.aborted) {
            return void 0;
          }
          setPromiseMeta(suspended, { status: "rejected", reason });
          throw reason;
        }
      );
    }
    return Promise.reject(e);
  }
}
function eagerAtom(...args) {
  const [read, write] = args;
  return atom(
    (get, { signal }) => {
      const eagerGet = ((atomToGet) => unwrapPromise(get(atomToGet)));
      eagerGet.all = (atoms) => atoms.map((a) => get(a)).map((v) => unwrapPromise(v));
      eagerGet.await = (promiseOrValue) => unwrapPromise(promiseOrValue);
      eagerGet.awaitAll = (values) => values.map((v) => unwrapPromise(v));
      return resolveSuspension(() => read(eagerGet), signal);
    },
    write ?? (() => void 0)
  );
}
function isEagerError(error) {
  return !!error?.[NotYet];
}

const defaultFallback = () => void 0;
function withPending(anAtom, fallback = defaultFallback) {
  const refreshAtom = atom(0);
  if (import.meta.env?.MODE !== "production") {
    refreshAtom.debugPrivate = true;
  }
  const promiseAndValueAtom = atom(
    (get, { setSelf }) => {
      get(refreshAtom);
      const prev = get(promiseAndValueAtom);
      const promise = get(anAtom);
      if (!isPromiseLike(promise)) {
        return { v: promise };
      }
      const meta = getPromiseMeta(promise);
      if (meta?.status === "fulfilled") {
        return { p: promise, v: meta.value };
      }
      if (meta?.status === "rejected") {
        throw meta.reason;
      }
      if (promise !== prev?.p) {
        promise.then(
          (value) => {
            setPromiseMeta(promise, { status: "fulfilled", value });
            setSelf();
          },
          (reason) => {
            setPromiseMeta(promise, { status: "rejected", reason });
            setSelf();
          }
        );
      }
      if (prev && "v" in prev) {
        return {
          p: promise,
          f: fallback({
            get,
            prev: prev.v,
            pending: promise
          }),
          v: prev.v
        };
      }
      return {
        p: promise,
        f: fallback({
          get,
          prev: void 0,
          pending: promise
        })
      };
    },
    (_get, set) => {
      set(refreshAtom, (c) => c + 1);
    }
  );
  promiseAndValueAtom.init = void 0;
  if (import.meta.env?.MODE !== "production") {
    promiseAndValueAtom.debugPrivate = true;
  }
  return atom(
    (get) => {
      const state = get(promiseAndValueAtom);
      if ("f" in state) {
        return state.f;
      }
      return state.v;
    },
    (_get, set, ...args) => set(anAtom, ...args)
  );
}

const cache1 = /* @__PURE__ */ new WeakMap();
const memo1 = (create, dep1) => (cache1.has(dep1) ? cache1 : cache1.set(dep1, create())).get(dep1);
const Pending = Symbol("The loadable is pending");
function loadable(anAtom) {
  return memo1(() => {
    const atomWithPending = withPending(anAtom, () => Pending);
    if (import.meta.env?.MODE !== "production") {
      atomWithPending.debugPrivate = true;
    }
    return atom((get) => {
      let value;
      try {
        value = get(atomWithPending);
      } catch (error) {
        return { state: "hasError", error };
      }
      if (value === Pending) {
        return { state: "loading" };
      }
      return { state: "hasData", data: value };
    });
  }, anAtom);
}

export { derive, eagerAtom, isEagerError, loadable, soon, soonAll, withPending };