Can I export an object using `export` as "`module.export`"

Question

I think what I am asking for is not possible OOB, but I want to confirm.

We are in a process of upgrading to ES6 (using Babel). Project is a web-site, using AMD (requirejs). I would like to turn a utility module (foolib) into ES6, but consume it from either ES6 (using import) or existing ES5/AMD module.

// foolib.es6
export { // as expected, this doesn't work
    method1: function () { ... },
    value1: 123.456
};

// consumer1.es6
import foolib from "foolib";

// consumer2.js
define(["foolib"], function (foolib) {});

I understand that the solution is to change foolib.es6 as follows:

export function method1() { ... };
export let value1 = 123.456;

However in reality number of entries returned from foolib is ridiculous. So I was hoping there is a way to export existing object literal without rewriting every line.

Furthermore, I realize that this is most likely impossible, due to the differences between AMD import (using define) and import mechanism (later works with exports object that has values hanging off of it, including default value, while former expects a single value to be returned).

One possible solution that I think might work is to export my object as default from foolib.es6, and then tweak requirejs default loader to inspect imported value for being an esModule and return default value: value && value.__esModule && value.default || value. Should this work? (I'm still hoping there is an easier solution).

export default { method1: function () {}, ... } and babel-plugin-add-module-exports — sdgluck
– sdgluck, Commented Sep 2, 2016 at 14:32
@sdgluck: yep, that did it. Works with both consumers. Make it an answer please. Please include a gotcha that this plugin must be included before any -modules- plugin (transform-es2015-modules-amd in my case). — THX-1138
– THX-1138, Commented Sep 2, 2016 at 15:13

Michał Perłakowski · Accepted Answer · 2016-09-02 18:59:48Z

The syntax you are using to export the object is invalid because you are not giving the object a name, so it cannot be a named export, and you are not specifying that it is the default export, so it cannot be the default export. Change it to be the default export:

// foolib.es6
export default {
  method1: function () {}, 
  value1: 123.456
}

// consumer.es6
import foolib from "foolib";

console.log(foolib.value) //=> 123.456

You can use the babel-plugin-add-module-exports Babel plugin to reinstate a default export as the value of module.exports in Node-land.

And as you discovered, make sure you include this plugin before any other -modules- plugins, for example transform-es2015-modules-amd.

shriek · Accepted Answer · 2017-07-10 14:26:25Z

1

This might be late but alternatively you can use the named export as well which is a little different from the default approach that @sdgluck mentioned.

const method1 = function () {};
const value1 = 123.456;

export { method1, value1 };

I like this approach because you can import them directly like

import { method1, value1 } from 'foolib';

without reaching out to the default variable.

answered Jul 10, 2017 at 14:26

shriek

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