hell.js

const mockRootNavigator1 = function() {
  return {
    router: {
      getComponentForState: jest.fn
    }
  }
}
function mockRootNavigator2() {
  return {
    router: {
      getComponentForState: jest.fn
    }
  }
}
const mockRootNavigator3 = () => {
  return {
    router: {
      getComponentForState: jest.fn
    }
  }
}
//jest.mock('../../navigators/root_navigator', () => {  //if I uncomment this it'll work
  //return {
    //router: {
      //getComponentForState: jest.fn
    //}
  //}
//})
jest.mock('../../navigators/root_navigator', mockRootNavigator1) // this will fail
//jest.mock('../../navigators/root_navigator', mockRootNavigator2) // this will fail
//jest.mock('../../navigators/root_navigator', mockRootNavigator3) // this will fail

Here's my test error:

● Test suite failed to run

    /Users/dwellisz/p/react-mobile/src/actions/__tests__/navigation_test.js: babel-plugin-jest-hoist: The second argument of `jest.mock` must be a function.

If I use lines 8-14 instead of line 15 it works

As far as I can tell the only difference is a named function vs an anonymous function