问如何与useEffect/setState挂钩

EN

import { useEffect, useState } from "react";

export function useComponentResources(required) {
  const [componentResources, setComponentResources] = useState(null);

  useEffect(() => {
    if (required) {
      // api call
      setTimeout(() => setComponentResources({}), 100);
    }
  }, [required]);

  return componentResources;
}

import { renderHook } from "@testing-library/react-hooks";
import { useComponentResources } from "./component-resources.hook";

describe("component-resources.hook", () => {
  it("fetches resources when required", () => {
    //act
    const { result } = renderHook(() => useComponentResources(true));

    //assert
    expect(result.current).toEqual({});
  });
});

expect(received).toEqual(expected)

Expected value to equal:
  {}
Received:
  null

Difference:

  Comparing two different types of values. Expected object but received null.

   7 |     const { result } = renderHook(() => useComponentResources(true));
   9 |     //assert
> 10 |     expect(result.current).toEqual({});
  11 |   });
  12 | });