ES6-only createElement function

createElement.js

const createElement = (tagname = '') => {
  return (...content) => {
    const el = document.createElement(tagname);
    
    if (content[0] instanceof Object && !(content[0] instanceof HTMLElement)) {
      let attributes = content.shift();
      
      for (let attr in attributes) {
        switch (attr) {
          case 'events':
            if (!(attributes[attr] instanceof Object)) {
              throw new Error('Error: attribute "events" is not an object');
            } else {
              for (let event in attributes[attr]) {
                el.addEventListener(event, attributes[attr][event]);
              }
            }
            break;
          
          case 'styles':
            if (!(attributes[attr] instanceof Object)) {
              throw new Error('Error: attribute "styles" is not an object');
            } else {
              for (let style in attributes[attr]) {
                el.style[style] = attributes[attr][style];
              }
            }
            break;
          
          case 'className':
            attributes[attr].split(/\s/).forEach(className => el.classList.add(className));
            break;
          
          default:
            el.setAttribute(attr, attributes[attr]);
        }
      }
    }
    
    content.forEach(child => {
      if (child instanceof HTMLElement) {
        el.appendChild(child);
      } else if (typeof child === 'string' || typeof child === 'number') {
        const span = document.createElement('span');
        span.innerText = child;
        el.appendChild(span);
      } else if (Array.isArray(child)) {
        child.forEach(c => el.appendChild(c));
      } else {
        // do nothing
      }
    });
    
    return el;
  }
}

export default createElement;

usage.js

import createElement from './createElement.js';

const [div, h2, img, button] = ['div', 'h2', 'img', 'button'].map(el => createElement(el));

const html = div({
  className: 'wrapper big'
},
  h2({
    styles: {
      textDecoration: 'underline',
      fontFamily: 'monospace'
    }
  }, 'Hello, world!'),
  img({
    src: 'data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACH5BAEAAAAALAAAAAABAAEAAAICRAEAOw==',
    title: 'Empty pixel'
  }),
  button({
    events: {
      click: () => alert(1)
    }
  }, 'Click!'),
  div(div(div(div('Nesting...'))))
);

document.body.appendChild(html);