ES6+ javascript module export options

Question

I've seen public exports of ES6 modules done in both of the following ways:

// method 1 export var getAnswer = function () { return 'forty two'; };  // method 2 export default function () { return 'forty two'; }; 

1. Are both of these valid?
2. If so, why do they both exist?
3. Are there other valid options for module exports using ES6 syntax?

I'm surprised I haven't been able to find the answer with my googlefu. I'm concerned only with ES6 modules, not CommonJS, RequireJS, AMD, Node, etc.

Answer 1

A year and some later, here is the best information I've found on the subject.

There are 4 types of exports. Here are usage examples of each, along with some imports that use them:

Export Syntax

// default exports export default 42; export default {}; export default []; export default (1 + 2); export default foo; export default function () {} export default class {} export default function foo () {} export default class foo {}  // variables exports export var foo = 1; export var foo = function () {}; export var bar; export let foo = 2; export let bar; export const foo = 3; export function foo () {} export class foo {}  // named exports export {}; export {foo}; export {foo, bar}; export {foo as bar}; export {foo as default}; export {foo as default, bar};  // exports from export * from "foo"; export {} from "foo"; export {foo} from "foo"; export {foo, bar} from "foo"; export {foo as bar} from "foo"; export {foo as default} from "foo"; export {foo as default, bar} from "foo"; export {default} from "foo"; export {default as foo} from "foo"; 

Import Syntax

// default imports import foo from "foo"; import {default as foo} from "foo";  // named imports import {} from "foo"; import {bar} from "foo"; import {bar, baz} from "foo"; import {bar as baz} from "foo"; import {bar as baz, xyz} from "foo";  // glob imports import * as foo from "foo";  // mixing imports import foo, {baz as xyz} from "foo"; import foo, * as bar from "foo";  // just import import "foo"; 

Source.