Unable to use jest with reselect

[clems36]

Hi,

I'm trying to run my jest tests but this error appears multiple times in random test files that don't even include selectors: Selector creators expect all input-selectors to be functions, instead received the following types: [undefined].

Now i've encountered this issue before while running my react-native app but I never had it while running my tests. The way I had solved it was by declaring my selectors in a different order. Obviously I can't do that again for my tests because that would most likely mess it up for my app.

What I don't understand is why

• This error appears while running tests and not while running my app
• This error appears on test files that are no where near using any selector

Mocking createSelector is not an option because some of my tests actually test selectors.

I'm running on reselect version 4.0.0.

Cheers!

[markerikson]

Without seeing any actual code, I would assume it has something to do with dependencies between files and declaration orders.

[clems36]

Thanks for your answer! I have noticed that the test files that are failing always import a function from a file that imports a selector, or imports another file that imports a selector, etc ... But the test file itself does not use the selector.

For instance, the following is happening: Inside helper.test.js i'm importing normalizePlan and testing it as follows:

import { normalizePlan } from '../helpers';

describe('Test redux user helpers', () => {
  it('normalizes plan names', () => {
    expect(normalizePlan('myPlan')).toEqual(
      'myPlan',
    );
  });
});

and inside of helpers.js (where normalizePlan is declared), i'm importing getActivityStartingDate which is used in another function of that file, so it has nothing to do with normalizePlan. Also, getActivityStartingDate is not even a selector but it is declared in a file that contains selectors that use createSelector, which seems to be the issue.

[clems36]

I ended up finding the selector that caused the issue and mocking it, which I didn't want to do in the first place. This is not really a solution imo.

[markerikson]

It's still unclear what the actual problem is here, so I'm going to close this.

[areksvk]

I had the same problem and had to solve it by mocking the imported files. Not very ideal.

[markerikson]

@areksvk comments that just say "I have the same problem" really aren't helpful :(

Actual code examples and repos that demonstrate the problem are the only way we can try to understand what's going on and provide help.

[areksvk]

@markerikson My bad. I have one dummy test:

import * as service from './heatmap.service';

describe('dummy test', () => {
    expect(1 + 2).toBe(3);
});

But it is failing with this error:

Selector creators expect all input-selectors to be functions, instead received the following types: [function, undefined]

      38 | );
      39 |
    > 40 | const getArrayWithAvailableGranularities = reselect.createSelector(
         |                                                     ^
      41 |     [getArray, granularitiesSelectors.getArray], (indicators, granularities) => _.map(indicators, (indicator) =>
      42 |         _.assign({}, indicator, {
      43 |             availableGranularities: _.map(_.filter(granularities, (granularity) =>

      at getDependencies (node_modules/reselect/lib/index.js:53:11)
      at Object.createSelector (node_modules/reselect/lib/index.js:71:24)
      at Object.<anonymous> (app/js/redux/entities/indicatorsSelectors.service.ts:40:53)
      at Object.<anonymous> (app/js/redux/selectors/filterGroupSelectors.service.ts:8:1)
      at Object.<anonymous> (app/js/redux/filterGroupReducers.service.ts:2:1)
      at Object.<anonymous> (app/js/redux/combineReducers.service.ts:12:1)
      at Object.<anonymous> (app/js/config/reduxStore.config.ts:3:1)
      at Object.<anonymous> (app/js/remote/bootstrap/bootstrap.service.js:5:1)
      at Object.<anonymous> (app/js/remote/rest/rest.service.js:2:1)
      at Object.<anonymous> (app/js/remote/rest/metadataRest.service.js:2:1)
      at Object.<anonymous> (app/js/common/metadata/dataset.service.ts:3:1)
      at Object.<anonymous> (app/js/redux/entities/granularitiesSelectors.service.ts:1:1)
      at Object.<anonymous> (app/js/components/map/mapActions.service.js:1:1)
      at Object.<anonymous> (app/js/components/map/map.service.js:3:1)
      at Object.<anonymous> (app/js/components/map/heatmap.service.ts:1:1)
      at Object.<anonymous> (app/js/components/map/heatmap.service.test.js:1:1)

getArrayWithAvailableGranularities is selector from indicatorsSelectors.service.ts, and uses getArray selector from granularitiesSelectors.

But this error appears only while running tests, not while running app.

[theahmadzai]

Any solution?