recoil/cjs/recoil_values/__tests__/Recoil_selector-test.js.flow

Recoil - A state management library for React

/**
 * Copyright (c) Facebook, Inc. and its affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 * @emails oncall+recoil
 * @flow strict-local
 * @format
 */
'use strict';

import type { Loadable } from '../../adt/Recoil_Loadable';
import type { RecoilValue } from '../../core/Recoil_RecoilValue';

const {
  getRecoilTestFn
} = require('recoil-shared/__test_utils__/Recoil_TestingUtils');

let store, atom, noWait, act, constSelector, errorSelector, getRecoilValueAsLoadable, setRecoilValue, selector, asyncSelector, resolvingAsyncSelector, flushPromisesAndTimers, DefaultValue, freshSnapshot;
const testRecoil = getRecoilTestFn(() => {
  const {
    makeStore
  } = require('recoil-shared/__test_utils__/Recoil_TestingUtils');

  ({
    act
  } = require('ReactTestUtils'));
  atom = require('../Recoil_atom');
  constSelector = require('../Recoil_constSelector');
  errorSelector = require('../Recoil_errorSelector');
  ({
    getRecoilValueAsLoadable,
    setRecoilValue
  } = require('../../core/Recoil_RecoilValueInterface'));
  selector = require('../Recoil_selector');
  ({
    freshSnapshot
  } = require('../../core/Recoil_Snapshot'));
  ({
    asyncSelector,
    resolvingAsyncSelector,
    flushPromisesAndTimers
  } = require('recoil-shared/__test_utils__/Recoil_TestingUtils'));
  ({
    noWait
  } = require('../Recoil_WaitFor'));
  ({
    DefaultValue
  } = require('../../core/Recoil_Node'));
  store = makeStore();
});
declare function getLoadable<T>(recoilValue: RecoilValue<T>): Loadable<T>;
declare function getValue<T>(recoilValue: RecoilValue<T>): T;
declare function getPromise<T>(recoilValue: RecoilValue<T>): Promise<T>;
declare function getError(recoilValue: any): Error;
declare function setValue(recoilState: any, value: any): any;
declare function resetValue(recoilState: any): any;
testRecoil('selector get', () => {
  const staticSel = constSelector('HELLO');
  const selectorRO = selector({
    key: 'selector/get',
    get: ({
      get
    }) => get(staticSel)
  });
  expect(getValue(selectorRO)).toEqual('HELLO');
});
testRecoil('selector set', () => {
  const myAtom = atom({
    key: 'selector/set/atom',
    default: 'DEFAULT'
  });
  const selectorRW = selector({
    key: 'selector/set',
    get: ({
      get
    }) => get(myAtom),
    set: ({
      set
    }, newValue) => set(myAtom, newValue instanceof DefaultValue ? newValue : 'SET: ' + newValue)
  });
  expect(getValue(selectorRW)).toEqual('DEFAULT');
  setValue(myAtom, 'SET ATOM');
  expect(getValue(selectorRW)).toEqual('SET ATOM');
  setValue(selectorRW, 'SET SELECTOR');
  expect(getValue(selectorRW)).toEqual('SET: SET SELECTOR');
  resetValue(selectorRW);
  expect(getValue(selectorRW)).toEqual('DEFAULT');
});
testRecoil('selector reset', () => {
  const myAtom = atom({
    key: 'selector/reset/atom',
    default: 'DEFAULT'
  });
  const selectorRW = selector({
    key: 'selector/reset',
    get: ({
      get
    }) => get(myAtom),
    set: ({
      reset
    }) => reset(myAtom)
  });
  expect(getValue(selectorRW)).toEqual('DEFAULT');
  setValue(myAtom, 'SET ATOM');
  expect(getValue(selectorRW)).toEqual('SET ATOM');
  setValue(selectorRW, 'SET SELECTOR');
  expect(getValue(selectorRW)).toEqual('DEFAULT');
});
testRecoil('selector - evaluate to RecoilValue', () => {
  const atomA = atom({
    key: 'selector/const atom A',
    default: 'A'
  });
  const atomB = atom({
    key: 'selector/const atom B',
    default: 'B'
  });
  const inputAtom = atom({
    key: 'selector/input',
    default: 'a'
  });
  const mySelector = selector<string>({
    key: 'selector/output recoil value',
    get: ({
      get
    }) => get(inputAtom) === 'a' ? atomA : atomB
  });
  expect(getValue(mySelector)).toEqual('A');
  setValue(inputAtom, 'b');
  expect(getValue(mySelector)).toEqual('B');
});
describe('Catching Deps', () => {
  testRecoil('selector - catching exceptions', () => {
    const throwingSel = errorSelector('MY ERROR');
    expect(getValue(throwingSel)).toBeInstanceOf(Error);
    const catchingSelector = selector({
      key: 'selector/catching selector',
      get: ({
        get
      }) => {
        try {
          return get(throwingSel);
        } catch (e) {
          expect(e instanceof Error).toBe(true);
          expect(e.message).toContain('MY ERROR');
          return 'CAUGHT';
        }
      }
    });
    expect(getValue(catchingSelector)).toEqual('CAUGHT');
  });
  testRecoil('selector - catching exception (non Error)', () => {
    const throwingSel = selector({
      key: '__error/non Error thrown',
      get: () => {
        // eslint-disable-next-line no-throw-literal
        throw 'MY ERROR';
      }
    });
    const catchingSelector = selector({
      key: 'selector/catching selector',
      get: ({
        get
      }) => {
        try {
          return get(throwingSel);
        } catch (e) {
          expect(e).toBe('MY ERROR');
          return 'CAUGHT';
        }
      }
    });
    expect(getValue(catchingSelector)).toEqual('CAUGHT');
  });
  testRecoil('selector - catching loads', () => {
    const loadingSel = resolvingAsyncSelector('READY');
    expect(getValue(loadingSel) instanceof Promise).toBe(true);
    const blockedSelector = selector({
      key: 'selector/blocked selector',
      get: ({
        get
      }) => get(loadingSel)
    });
    expect(getValue(blockedSelector) instanceof Promise).toBe(true);
    const bypassSelector = selector({
      key: 'selector/bypassing selector',
      get: ({
        get
      }) => {
        try {
          return get(loadingSel);
        } catch (promise) {
          expect(promise instanceof Promise).toBe(true);
          return 'BYPASS';
        }
      }
    });
    expect(getValue(bypassSelector)).toBe('BYPASS');
    act(() => jest.runAllTimers());
    expect(getValue(bypassSelector)).toEqual('READY');
  });
});
describe('Dependencies', () => {
  // Test that Recoil will throw an error with a useful debug message instead of
  // infinite recurssion when there is a circular dependency
  testRecoil('Detect circular dependencies', () => {
    const selectorA = selector({
      key: 'circular/A',
      get: ({
        get
      }) => get(selectorC)
    });
    const selectorB = selector({
      key: 'circular/B',
      get: ({
        get
      }) => get(selectorA)
    });
    const selectorC = selector({
      key: 'circular/C',
      get: ({
        get
      }) => get(selectorB)
    });
    const devStatus = window.__DEV__;
    window.__DEV__ = true;
    expect(getValue(selectorC)).toBeInstanceOf(Error);
    expect(getError(selectorC).message).toEqual(expect.stringContaining('circular/A'));
    window.__DEV__ = devStatus;
  });
  testRecoil('distinct loading dependencies are treated as distinct', async () => {
    const upstreamAtom = atom({
      key: 'distinct loading dependencies/upstreamAtom',
      default: 0
    });
    const upstreamAsyncSelector = selector({
      key: 'distinct loading dependencies/upstreamAsyncSelector',
      get: ({
        get
      }) => Promise.resolve(get(upstreamAtom))
    });
    const directSelector = selector({
      key: 'distinct loading dependencies/directSelector',
      get: ({
        get
      }) => get(upstreamAsyncSelector)
    });
    expect(getValue(directSelector) instanceof Promise).toBe(true);
    act(() => jest.runAllTimers());
    expect(getValue(directSelector)).toEqual(0);
    setValue(upstreamAtom, 1);
    expect(getValue(directSelector) instanceof Promise).toBe(true);
    act(() => jest.runAllTimers());
    expect(getValue(directSelector)).toEqual(1);
  });
  testRecoil('selector - kite pattern runs only necessary selectors', async () => {
    const aNode = atom({
      key: 'aNode',
      default: true
    });
    let bNodeRunCount = 0;
    const bNode = selector({
      key: 'bNode',
      get: ({
        get
      }) => {
        bNodeRunCount++;
        const a = get(aNode);
        return String(a);
      }
    });
    let cNodeRunCount = 0;
    const cNode = selector({
      key: 'cNode',
      get: ({
        get
      }) => {
        cNodeRunCount++;
        const a = get(aNode);
        return String(Number(a));
      }
    });
    let dNodeRunCount = 0;
    const dNode = selector({
      key: 'dNode',
      get: ({
        get
      }) => {
        dNodeRunCount++;
        const value = get(aNode) ? get(bNode) : get(cNode);
        return value.toUpperCase();
      }
    });
    let dNodeValue = getValue(dNode);
    expect(dNodeValue).toEqual('TRUE');
    expect(bNodeRunCount).toEqual(1);
    expect(cNodeRunCount).toEqual(0);
    expect(dNodeRunCount).toEqual(1);
    setValue(aNode, false);
    dNodeValue = getValue(dNode);
    expect(dNodeValue).toEqual('0');
    expect(bNodeRunCount).toEqual(1);
    expect(cNodeRunCount).toEqual(1);
    expect(dNodeRunCount).toEqual(2);
  });
  testRecoil('selector does not re-run to completion when one of its async deps resolves to a previously cached value', async () => {
    const testSnapshot = freshSnapshot();
    testSnapshot.retain();
    const atomA = atom({
      key: 'atomc-rerun-opt-test',
      default: -3
    });
    const selectorB = selector({
      key: 'selb-rerun-opt-test',
      get: async ({
        get
      }) => {
        await Promise.resolve();
        return Math.abs(get(atomA));
      }
    });
    let numTimesCStartedToRun = 0;
    let numTimesCRanToCompletion = 0;
    const selectorC = selector({
      key: 'sela-rerun-opt-test',
      get: ({
        get
      }) => {
        numTimesCStartedToRun++;
        const ret = get(selectorB);
        /**
         * The placement of numTimesCRan is important as this optimization
         * prevents the execution of selectorC _after_ the point where the
         * selector execution hits a known path of dependencies. In other words,
         * the lines prior to the get(selectorB) will run twice, but the lines
         * following get(selectorB) should only run once given that we are
         * setting up this test so that selectorB resolves to a previously seen
         * value the second time that it runs.
         */

        numTimesCRanToCompletion++;
        return ret;
      }
    });
    testSnapshot.getLoadable(selectorC);
    /**
     * Run selector chain so that selectorC is cached with a dep of selectorB
     * set to "3"
     */

    await flushPromisesAndTimers();
    const loadableA = testSnapshot.getLoadable(selectorC);
    expect(loadableA.contents).toBe(3);
    expect(numTimesCRanToCompletion).toBe(1);
    /**
     * It's expected that C started to run twice so far (the first is the first
     * time that the selector was called and suspended, the second was when B
     * resolved and C re-ran because of the async dep resolution)
     */

    expect(numTimesCStartedToRun).toBe(2);
    const mappedSnapshot = testSnapshot.map(({
      set
    }) => {
      set(atomA, 3);
    });
    mappedSnapshot.getLoadable(selectorC);
    /**
     * Run selector chain so that selectorB recalculates as a result of atomA
     * being changed to "3"
     */

    mappedSnapshot.retain();
    await flushPromisesAndTimers();
    const loadableB = mappedSnapshot.getLoadable(selectorC);
    expect(loadableB.contents).toBe(3);
    /**
     * If selectors are correctly optimized, selectorC will not re-run because
     * selectorB resolved to "3", which is a value that selectorC has previously
     * cached for its selectorB dependency.
     */

    expect(numTimesCRanToCompletion).toBe(1);
    /**
     * TODO:
     * in the ideal case this should be:
     *
     * expect(numTimesCStartedToRun).toBe(2);
     */

    expect(numTimesCStartedToRun).toBe(3);
  });
  testRecoil('async dep that changes from loading to value triggers re-execution', async () => {
    const baseAtom = atom({
      key: 'baseAtom',
      default: 0
    });
    const asyncSel = selector({
      key: 'asyncSel',
      get: ({
        get
      }) => {
        const atomVal = get(baseAtom);

        if (atomVal === 0) {
          return new Promise(() => {});
        }

        return atomVal;
      }
    });
    const selWithAsyncDep = selector({
      key: 'selWithAsyncDep',
      get: ({
        get
      }) => {
        return get(asyncSel);
      }
    });
    const snapshot = freshSnapshot();
    snapshot.retain();
    const loadingValLoadable = snapshot.getLoadable(selWithAsyncDep);
    expect(loadingValLoadable.state).toBe('loading');
    const mappedSnapshot = snapshot.map(({
      set
    }) => {
      set(baseAtom, 10);
    });
    const newAtomVal = mappedSnapshot.getLoadable(baseAtom);
    expect(newAtomVal.valueMaybe()).toBe(10);
    const valLoadable = mappedSnapshot.getLoadable(selWithAsyncDep);
    expect(valLoadable.valueMaybe()).toBe(10);
  });
});
testRecoil('async set not supported', async () => {
  const myAtom = atom({
    key: 'selector / async not supported / other atom',
    default: 'DEFAULT'
  });
  const mySelector = selector({
    key: 'selector / async set not supported / async set method',
    get: () => myAtom,
    // Set should not be async, this test checks that it throws an error.
    // $FlowExpectedError
    set: async ({
      set,
      reset
    }, newVal) => {
      await Promise.resolve();
      newVal instanceof DefaultValue ? reset(myAtom) : set(myAtom, 'SET');
    }
  });
  let setAttempt, resetAttempt;
  const mySelector2 = selector({
    key: 'selector / async set not supported / async upstream call',
    get: () => myAtom,
    set: ({
      set,
      reset
    }, newVal) => {
      if (newVal instanceof DefaultValue) {
        resetAttempt = new Promise.resolve().then(() => {
          reset(myAtom);
        });
      } else {
        setAttempt = new Promise.resolve().then(() => {
          set(myAtom, 'SET');
        });
      }
    }
  });
  const testSnapshot = freshSnapshot();
  testSnapshot.retain();
  expect(() => testSnapshot.map(({
    set
  }) => {
    set(mySelector, 'SET');
  })).toThrow();
  expect(() => testSnapshot.map(({
    reset
  }) => {
    reset(mySelector);
  })).toThrow();
  const setSnapshot = testSnapshot.map(({
    set,
    reset
  }) => {
    set(mySelector2, 'SET');
    reset(mySelector2);
  });
  setSnapshot.retain();
  await flushPromisesAndTimers();
  expect(setSnapshot.getLoadable(mySelector2).contents).toEqual('DEFAULT');
  await expect(setAttempt).rejects.toThrowError();
  await expect(resetAttempt).rejects.toThrowError();
});
describe('User-thrown promises', () => {
  testRecoil('selectors with user-thrown loadable promises execute to completion as expected', async () => {
    const [asyncDep, resolveAsyncDep] = asyncSelector<string, void>();
    const selWithUserThrownPromise = selector({
      key: 'selWithUserThrownPromise',
      get: ({
        get
      }) => {
        const loadable = get(noWait(asyncDep));

        if (loadable.state === 'loading') {
          throw loadable.toPromise();
        }

        return loadable.valueOrThrow();
      }
    });
    const loadable = getLoadable(selWithUserThrownPromise);
    const promise = loadable.toPromise();
    expect(loadable.state).toBe('loading');
    resolveAsyncDep('RESOLVED');
    await flushPromisesAndTimers();
    const val: mixed = await promise;
    expect(val).toBe('RESOLVED');
  });
  testRecoil('selectors with user-thrown loadable promises execute to completion as expected', async () => {
    const myAtomA = atom({
      key: 'myatoma selectors user-thrown promise',
      default: 'A'
    });
    const myAtomB = atom({
      key: 'myatomb selectors user-thrown promise',
      default: 'B'
    });
    let isResolved = false;
    declare var resolve: () => any;
    const myPromise = new Promise(localResolve => {
      resolve = () => {
        isResolved = true;
        localResolve();
      };
    });
    const selWithUserThrownPromise = selector({
      key: 'selWithUserThrownPromise',
      get: ({
        get
      }) => {
        const a = get(myAtomA);

        if (!isResolved) {
          throw myPromise;
        }

        const b = get(myAtomB);
        return `${a}${b}`;
      }
    });
    const loadable = getLoadable(selWithUserThrownPromise);
    const promise = loadable.toPromise();
    expect(loadable.state).toBe('loading');
    resolve();
    await flushPromisesAndTimers();
    const val: mixed = await promise;
    expect(val).toBe('AB');
  });
  testRecoil('selectors with nested user-thrown loadable promises execute to completion as expected', async () => {
    const [asyncDep, resolveAsyncDep] = asyncSelector<string, void>();
    const selWithUserThrownPromise = selector({
      key: 'selWithUserThrownPromise',
      get: ({
        get
      }) => {
        const loadable = get(noWait(asyncDep));

        if (loadable.state === 'loading') {
          throw loadable.toPromise();
        }

        return loadable.valueOrThrow();
      }
    });
    const selThatDependsOnSelWithUserThrownPromise = selector({
      key: 'selThatDependsOnSelWithUserThrownPromise',
      get: ({
        get
      }) => get(selWithUserThrownPromise)
    });
    const loadable = getLoadable(selThatDependsOnSelWithUserThrownPromise);
    const promise = loadable.toPromise();
    expect(loadable.state).toBe('loading');
    resolveAsyncDep('RESOLVED');
    await flushPromisesAndTimers();
    const val: mixed = await promise;
    expect(val).toBe('RESOLVED');
  });
});
testRecoil('selectors cannot mutate values in get() or set()', () => {
  const devStatus = window.__DEV__;
  window.__DEV__ = true;
  const userState = atom({
    key: 'userState',
    default: {
      name: 'john',
      address: {
        road: '103 road',
        nested: {
          value: 'someNestedValue'
        }
      }
    }
  });
  const userSelector = selector({
    key: 'userSelector',
    get: ({
      get
    }) => {
      const user = get(userState);
      user.address.road = '301 road';
      return user;
    },
    set: ({
      set,
      get
    }) => {
      const user = get(userState);
      user.address.road = 'narrow road';
      return set(userState, user);
    }
  });
  const testSnapshot = freshSnapshot();
  testSnapshot.retain();
  expect(() => testSnapshot.map(({
    set
  }) => {
    set(userSelector, {
      name: 'matt',
      address: {
        road: '103 road',
        nested: {
          value: 'someNestedValue'
        }
      }
    });
  })).toThrow();
  expect(testSnapshot.getLoadable(userSelector).state).toBe('hasError');
  window.__DEV__ = devStatus;
});
describe('getCallback', () => {
  testRecoil('Selector getCallback', async () => {
    const myAtom = atom({
      key: 'selector - getCallback atom',
      default: 'DEFAULT'
    });
    const mySelector = selector({
      key: 'selector - getCallback',
      get: ({
        getCallback
      }) => {
        return {
          onClick: getCallback(({
            snapshot
          }) => async () => await snapshot.getPromise(myAtom))
        };
      }
    });
    const menuItem = getValue(mySelector);
    expect(getValue(myAtom)).toEqual('DEFAULT');
    await expect(menuItem.onClick()).resolves.toEqual('DEFAULT');
    act(() => setValue(myAtom, 'SET'));
    expect(getValue(myAtom)).toEqual('SET');
    await expect(menuItem.onClick()).resolves.toEqual('SET');
    act(() => setValue(myAtom, 'SET2'));
    expect(getValue(myAtom)).toEqual('SET2');
    await expect(menuItem.onClick()).resolves.toEqual('SET2');
  });
  testRecoil('snapshot', async () => {
    const otherSelector = constSelector('VALUE');
    const mySelector = selector({
      key: 'selector getCallback snapshot',
      get: ({
        getCallback
      }) => getCallback(({
        snapshot
      }) => param => ({
        param,
        loadable: snapshot.getLoadable(otherSelector),
        promise: snapshot.getPromise(otherSelector)
      }))
    });
    expect(getValue(mySelector)(123).param).toBe(123);
    expect(getValue(mySelector)(123).loadable.getValue()).toBe('VALUE');
    await expect(getValue(mySelector)(123).promise).resolves.toBe('VALUE');
  });
  testRecoil('set', () => {
    const myAtom = atom({
      key: 'selector getCallback set atom',
      default: 'DEFAULT'
    });
    const setSelector = selector({
      key: 'selector getCallback set',
      get: ({
        getCallback
      }) => getCallback(({
        set
      }) => param => {
        set(myAtom, param);
      })
    });
    const resetSelector = selector({
      key: 'selector getCallback reset',
      get: ({
        getCallback
      }) => getCallback(({
        reset
      }) => () => {
        reset(myAtom);
      })
    });
    expect(getValue(myAtom)).toBe('DEFAULT');
    getValue(setSelector)('SET');
    expect(getValue(myAtom)).toBe('SET');
    getValue(resetSelector)();
    expect(getValue(myAtom)).toBe('DEFAULT');
  });
  testRecoil('transaction', () => {
    const myAtom = atom({
      key: 'selector getCallback transact atom',
      default: 'DEFAULT'
    });
    const setSelector = selector({
      key: 'selector getCallback transact set',
      get: ({
        getCallback
      }) => getCallback(({
        transact_UNSTABLE
      }) => param => {
        transact_UNSTABLE(({
          set,
          get
        }) => {
          expect(get(myAtom)).toBe('DEFAULT');
          set(myAtom, 'TMP');
          expect(get(myAtom)).toBe('TMP');
          set(myAtom, param);
        });
      })
    });
    const resetSelector = selector({
      key: 'selector getCallback transact',
      get: ({
        getCallback
      }) => getCallback(({
        transact_UNSTABLE
      }) => () => {
        transact_UNSTABLE(({
          reset
        }) => reset(myAtom));
      })
    });
    expect(getValue(myAtom)).toBe('DEFAULT');
    getValue(setSelector)('SET');
    expect(getValue(myAtom)).toBe('SET');
    getValue(resetSelector)();
    expect(getValue(myAtom)).toBe('DEFAULT');
  });
  testRecoil('node', () => {
    const mySelector = selector({
      key: 'selector getCallback node',
      get: ({
        getCallback
      }) => getCallback(({
        node,
        snapshot
      }) => param => ({
        param,
        loadable: snapshot.getLoadable(node),
        promise: snapshot.getPromise(node)
      }))
    });
    expect(getValue(mySelector)(123).param).toBe(123);
    expect(getValue(mySelector)(123).loadable.getValue()(456).param).toBe(456);
  });
  testRecoil('refresh', async () => {
    let externalValue = 0;
    const mySelector = selector({
      key: 'selector getCallback node refresh',
      get: ({
        getCallback
      }) => {
        const cachedExternalValue = externalValue;
        return getCallback(({
          node,
          refresh
        }) => () => ({
          cached: cachedExternalValue,
          current: externalValue,
          refresh: () => refresh(node)
        }));
      }
    });
    expect(getValue(mySelector)().current).toBe(0);
    expect(getValue(mySelector)().cached).toBe(0);
    externalValue = 1;
    expect(getValue(mySelector)().current).toBe(1);
    expect(getValue(mySelector)().cached).toBe(0);
    getValue(mySelector)().refresh();
    expect(getValue(mySelector)().current).toBe(1);
    expect(getValue(mySelector)().cached).toBe(1);
  });
  testRecoil('Guard against calling during selector evaluation', async () => {
    const mySelector = selector({
      key: 'selector getCallback guard',
      get: ({
        getCallback
      }) => {
        const callback = getCallback(() => () => {});
        expect(() => callback()).toThrow();
        return 'THROW';
      }
    });
    expect(getValue(mySelector)).toBe('THROW');
    const myAsyncSelector = selector({
      key: 'selector getCallback guard async',
      get: async ({
        getCallback
      }) => {
        const callback = getCallback(() => () => {});
        await Promise.resolve();
        expect(() => callback()).toThrow();
        return 'THROW';
      }
    });
    await expect(getPromise(myAsyncSelector)).resolves.toBe('THROW');
  });
  testRecoil('Callback can be used from thrown error', async () => {
    const mySelector = selector({
      key: 'selector getCallback from error',
      get: ({
        getCallback
      }) => {
        // eslint-disable-next-line no-throw-literal
        throw {
          callback: getCallback(() => x => x)
        };
      }
    }); // $FlowExpectedError[incompatible-use]]

    expect(getLoadable(mySelector).errorOrThrow().callback(123)).toEqual(123);
    const myAsyncSelector = selector({
      key: 'selector getCallback from error async',
      get: ({
        getCallback
      }) => {
        return Promise.reject({
          callback: getCallback(() => x => x)
        });
      }
    });
    await expect(getPromise(myAsyncSelector).catch(({
      callback
    }) => callback(123))).resolves.toEqual(123);
  });
});
testRecoil('Selector values are frozen', async () => {
  const devStatus = window.__DEV__;
  window.__DEV__ = true;
  const frozenSelector = selector({
    key: 'selector frozen',
    get: () => ({
      state: 'frozen',
      nested: {
        state: 'frozen'
      }
    })
  });
  expect(Object.isFrozen(getValue(frozenSelector))).toBe(true);
  expect(Object.isFrozen(getValue(frozenSelector).nested)).toBe(true);
  const thawedSelector = selector({
    key: 'selector frozen thawed',
    get: () => ({
      state: 'thawed',
      nested: {
        state: 'thawed'
      }
    }),
    dangerouslyAllowMutability: true
  });
  expect(Object.isFrozen(getValue(thawedSelector))).toBe(false);
  expect(Object.isFrozen(getValue(thawedSelector).nested)).toBe(false);
  const asyncFrozenSelector = selector({
    key: 'selector frozen async',
    get: () => Promise.resolve({
      state: 'frozen',
      nested: {
        state: 'frozen'
      }
    })
  });
  await expect(getPromise(asyncFrozenSelector).then(x => Object.isFrozen(x))).resolves.toBe(true);
  expect(Object.isFrozen(getValue(asyncFrozenSelector).nested)).toBe(true);
  const asyncThawedSelector = selector({
    key: 'selector frozen thawed async',
    get: () => Promise.resolve({
      state: 'thawed',
      nested: {
        state: 'thawed'
      }
    }),
    dangerouslyAllowMutability: true
  });
  await expect(getPromise(asyncThawedSelector).then(x => Object.isFrozen(x))).resolves.toBe(false);
  expect(Object.isFrozen(getValue(asyncThawedSelector).nested)).toBe(false);
  const upstreamFrozenSelector = selector({
    key: 'selector frozen upstream',
    get: () => ({
      state: 'frozen',
      nested: {
        state: 'frozen'
      }
    })
  });
  const fwdFrozenSelector = selector({
    key: 'selector frozen fwd',
    get: () => upstreamFrozenSelector
  });
  expect(Object.isFrozen(getValue(fwdFrozenSelector))).toBe(true);
  expect(Object.isFrozen(getValue(fwdFrozenSelector).nested)).toBe(true);
  const upstreamThawedSelector = selector({
    key: 'selector frozen thawed upstream',
    get: () => ({
      state: 'thawed',
      nested: {
        state: 'thawed'
      }
    }),
    dangerouslyAllowMutability: true
  });
  const fwdThawedSelector = selector({
    key: 'selector frozen thawed fwd',
    get: () => upstreamThawedSelector,
    dangerouslyAllowMutability: true
  });
  expect(Object.isFrozen(getValue(fwdThawedSelector))).toBe(false);
  expect(Object.isFrozen(getValue(fwdThawedSelector).nested)).toBe(false); // Selectors should not freeze their upstream dependencies

  const upstreamMixedSelector = selector({
    key: 'selector frozen mixed upstream',
    get: () => ({
      state: 'thawed',
      nested: {
        state: 'thawed'
      }
    }),
    dangerouslyAllowMutability: true
  });
  const fwdMixedSelector = selector({
    key: 'selector frozen mixed fwd',
    get: ({
      get
    }) => {
      get(upstreamMixedSelector);
      return {
        state: 'frozen'
      };
    }
  });
  expect(Object.isFrozen(getValue(fwdMixedSelector))).toBe(true);
  expect(Object.isFrozen(getValue(upstreamMixedSelector))).toBe(false);
  expect(Object.isFrozen(getValue(upstreamMixedSelector).nested)).toBe(false);
  window.__DEV__ = devStatus;
});
testRecoil('Required options are provided when creating selectors', () => {
  const devStatus = window.__DEV__;
  window.__DEV__ = true; // $FlowExpectedError[incompatible-call]

  expect(() => selector({
    get: () => {}
  })).toThrow(); // $FlowExpectedError[incompatible-call]

  expect(() => selector({
    get: false
  })).toThrow(); // $FlowExpectedError[incompatible-call]

  expect(() => selector({
    key: 'MISSING GET'
  })).toThrow();
  window.__DEV__ = devStatus;
});