How to consume npm package with es6 module via Web

问题:

Let's say I want to use Immutable in my project (or any given npm package). I have npm installed it, so it is in node_modules. Of course, it has CommonJS exports there. I, however, want to use es6 modules in my project.

I am using Webpack to compile it all together, with the 6to5-loader to deal with es6 module syntax.

In my source file, I say import Immutable from 'immutable'; --- but this causes a problem because the es6 import is looking for an es6 default to have been exported, which isn't the case (for Immutable or probably almost any other npm package). The compiled code ends up looking like this: var Immutable = require('immutable')["default"]; --- which of course throws an error, since there is no default property to find.

Can I consume the npm packages with es6 modules?

回答1:

Babel.js contributor here. You're looking for the following:

import * as Immutable from 'immutable';
// compiles to:
var Immutable = require('immutable');

Interactive demo

Note: This is with either the common or commonInterop modules option. For others, see: https://babeljs.io/docs/usage/modules/

回答2:

Just figured it out. (The solution is tool-specific --- but es6 modules only exist now insofar as they are tool-enabled, so I think that's enough of an "answer".)

6to5's default module transpilation uses the common option, which results in the very problem I griped about above. But there is another option: commonInterop --- which must have been built to deal with exactly the situation I'm dealing with. See https://6to5.github.io/modules.html#common-interop

So three cheers for 6to5.