jquery.widgets.js

import $ from 'jquery';

class HogeWidget {
  constructor(el) {
    this.$el = $(el); 
  }
  bind() {
    this.$el.on('click', () => { ... });
  }
  init() {
    this.bind();
  }
}

// initializer
$('[data-widget="hoge"]').each(function(el) {
  let w = new HogeWidget(el);
  w.init();
});