jdom parsing fails when setting attribute name using a variable

[micuat]

first of all thanks for the amazing framework!

I found that jdom parsing fails when I try to set an attribute name using a variable:

class Button extends Torus.StyledComponent {
  init(on, msg) {
    this.on = on;
    this.msg = msg;
  }
  // OK
  compose() {
    return jdom`
    <button disabled=${!this.on}>${this.msg}</button>
    `;
  }
  // NG
  // compose() {
  //   return jdom`
  //   <button ${this.on ? null : "disabled"}>${this.msg}</button>
  //   `;
  // }
  // OK
  // compose() {
  //   return {
  //     tag: "button",
  //     attrs: {
  //       disabled: !this.on
  //     },
  //     children: [this.msg]
  //   }
  // }
}

class App extends Torus.StyledComponent {
  init() {
    this.b0 = new Button(true, "enabled");
    this.b1 = new Button(false, "disabled");
  }
  compose() {
    return jdom`
    <div>
    ${this.b0.node}
    ${this.b1.node}
    </div>
    `;
  }
}
const app = new App;

document.getElementById("app").appendChild(app.node);

https://codepen.io/naotohieda/pen/RwZLVvj

It seems neither <button ${keyName}> nor <button ${keyName}=${value}> works. As long as <button key=${value}> works, it's no problem for me (I don't see it as a bug), but I thought it may be good to mention in the doc. Thanks!