Abstract Factory, with self-registration!

blog-post-importer.es6

let subclasses = {};
export default class BlogPostImporter {
  constructor(body) {
    for(var p in body) {
      if(body.hasOwnProperty(p)) {
        this[p] = body[p];
      }
    }
  }
  
  static define(name, body) {
    return new BlogPostImporter(body).register(name);
  }
  
  static create(type) {
    let Klass = subclasses[type];
    if(!Klass) {
      throw `Bad importer type ${type}`;
    }
    return new Klass();
  }
  
  register(name) {
    subclasses[name] = this;
    return this;
  }
};

wordpress-importer.es6

import {default as BlogPostImporter} from './blog-post-importer';

export default BlogPostImporter.define('wordpress', {
  import: (content, import_types, date_type) => {
    // code to import word press posts from XML
  },
  
  make_post: (el, use_original_date) => {
    // code to insert a new post in our DB
  }
});