Creating a DOM-like element tree from JSONML

jsonmlElement.js

function isObject(obj) {
  if (!obj) return false;
  if (typeof obj !== "object") return false;
  if (Array.isArray(obj)) return false;
  return true;
}

class Element {
  constructor(tagName, attributes, ...children) {
    this.tagName = tagName;
    this.attributes = { ...attributes };
    this.children = children;
  }
  get innerText() {
    return this.children.reduce(
      (textContent, child) =>
        textContent +
        (child instanceof Element ? child.innerText : String(child)),
      ""
    );
  }
  find(tagName, ...tagNames) {
    if (tagName === "#") return this.innerText;
    const child = this.children.find(
      child => child instanceof Element && child.tagName === tagName
    );
    if (!child) return undefined;
    if (!tagNames.length) return child;
    return child.find(...tagNames);
  }
}

function createElement(tagName, ...children) {
  const attributes = {};
  if (isObject(children[0])) {
    Object.assign(attributes, children.shift());
  }
  return new Element(
    tagName,
    attributes,
    ...children.map(child => {
      if (!Array.isArray(child)) return String(child);
      return createElement(...child);
    })
  );
}