Q: import es6 module returns undefined in one file, but not the other I have the following files in my project:
Account.js
import User from './User';

const associations = {
    user: {
    type: 'belongsTo',
    model: User
  }
};

class Account {

}

Account.associations = associations;

export default Account;

User.js
import TwitterAccount from './TwitterAccount';

const associations = {
    accounts: {
    type: 'hasMany',
    model: TwitterAccount
  }
};

class User {

}

User.associations = associations;

export default User;

The problem I'm encountering is that User.associations returns {accounts: { type: 'hasMany', model: [Object]}}, however Account.associations returns: {users: { type: 'belongsTo', model: undefined }}.
Now I did try the imports to const User = require('./User') and const Account = require('./Account'), and this solves the problem but I'm not understanding what is causing this to happen in the first place? I've never had this problem before. 
