Adding CodeMirror to Shadow Dom of Custom Element?

Question

I\'d like to dynamically create a CodeMirror instance inside a Custom Element and have it live inside the element\'s Shadow DOM. For example:

Answer 1

Import CodeMirror's stylesheet inside the shadow DOM with @import url:

constructor() {
    super();
    let shadowRoot = this.attachShadow({ mode: 'open' });
    shadowRoot.innerHTML = `
        <style>
           @import url(https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.24.2/codemirror.min.css)
        </style>`         
}