@mittwald/react-use-promise/dist/esm/resource/getAsyncResource.test.js

Simple and declarative use of Promises in your React components. Observe their state and refresh them in various advanced ways.

import { beforeEach, expect, jest, test } from "@jest/globals";
import { sleep } from "../lib/testing.js";
import { getAsyncResource } from "./getAsyncResource.js";
import { asyncResourceStore } from "./store.js";
const sleepTime = 2000;
beforeEach(() => {
    jest.useFakeTimers();
    asyncResourceStore.clear();
});
afterEach(() => {
    jest.runOnlyPendingTimers();
    jest.useRealTimers();
});
const loader = jest.fn(async (value) => {
    await sleep(sleepTime);
    return value;
});
const load = async (resource) => {
    const loadingPromise = resource.load();
    jest.advanceTimersToNextTimer();
    await loadingPromise;
};
test("Expect loader is not called when parameters is null", async () => {
    const resource = getAsyncResource(loader, null);
    await load(resource);
    expect(loader).not.toHaveBeenCalled();
});
test("Expect value is undefined when parameters is null", async () => {
    const resource = getAsyncResource(loader, null);
    await load(resource);
    const value = resource.value.value.isSet
        ? resource.value.value.value
        : undefined;
    expect(resource.value.value.isSet).toBe(true);
    expect(value).toBe(undefined);
});