Question

93

Difference between import X and import * as X in node.js (ES6 / Babel)?

rated 0 times [ 100] [ 7] / answers: 1 / hits: 34071 / 9 Years ago, mon, july 13, 2015, 12:00:00

I have a node.js library lib written in ES6 (compiled with Babel) in which I export the following submodules:

use strict;



import * as _config from './config';

import * as _db from './db';

import * as _storage from './storage';



export var config = _config;

export var db = _db;

export var storage = _storage;

If from my main project I include the library like this

import * as lib from 'lib';

console.log(lib);

I can see the proper output and it work as expected { config: ... }. However, if I try to include the library like this:

import lib from 'lib';

console.log(lib);

it will be undefined.

Can someone explain what is happening here? Aren't the two import methods supposed to be equivalent? If not, what difference am I missing?

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ulysses

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4 Years ago

answered 9 Years ago ryderalfonsos · Accepted Answer

import * as lib from 'lib';

is asking for an object with all of the named exports of 'lib'.

export var config = _config;

export var db = _db;

export var storage = _storage;

are named exports, which is why you end up with an object like you did.

import lib from 'lib';

is asking for the default export of lib.

e.g.

export default 4;

would make lib === 4. It does not fetch the named exports. To get an object from the default export, you'd have to explicitly do

export default {

  config: _config,

  db: _db,

  storage: _storage

};