ES Modules, or ECMAScript Modules

foo.js

class ArticleNode {
    constructor(node, paragraph) {
        this.node = node
        this.paragraph = paragraph
    }
}

export function createOneArticleNode(){
    let articleNode0 = new ArticleNode('foo', 'bar')
    console.log('a n: ', articleNode0)
}

bar.js

// jest test
import { createOneArticleNode } from '../content_module.js' 

test('test es module 0', () => {
    console.log('print foo')
    createOneArticleNode()
    console.log('print bar')
});

npm run test