es6 import, export default,

Question

https://github.com/rt2zz/redux-persist shows the following code snippet

const persistedReducer = persistReducer(persistConfig, rootReducer)

export default () => {
  let store = createStore(persistedReducer)
  let persistor = persistStore(store)
  return { store, persistor }
}

You could instead do this, and what is the difference between the two?

const persistedReducer = persistReducer(persistConfig, rootReducer)

let store = createStore(persistedReducer)
let persistor = persistStore(store)
export { store, persistor }

• EDIT

more importantly, why would one use the first form instead of the 2nd?

Answer 1

The first snippet is exporting a function which returns a object . The second snippet returns a object directly.

When import first snippet, You need to call the function to get the object. Meanwhile You can directly import object from second snippet.

Answer 2

vi a.mjs then write:

export default () => {
  let store = 'createStore';
  let persistor = 'persistStore';
  return { store, persistor }
}

let store = 'createStore';
let persistor = 'persistStore';
export { store, persistor }

vi b.mjs then write:

import a from './a.mjs';
import * as $a from './a.mjs';
import { store, persistor } from './a.mjs';

console.log('export default function:', a);
console.log('export object:', $a);
console.log('export object.default:', $a.default);
console.log('export { store, persistor }:', store, persistor);

node --experimental-modules b.mjs

And the you will be get the result like this:

export default function: [Function: default]
export object: [Module] {
  default: [Function: default],
  persistor: 'persistStore',
  store: 'createStore'
}
export object.default: [Function: default]
export { store, persistor }: createStore persistStore