A stencil functional component for rendering the children element's markup in a <code> element along side the rendered jsx

as-source.tsx

import { h, ChildNode, FunctionalComponent, FunctionalUtilities } from "@stencil/core";

function vnodeToSource(elem: ChildNode, utils: FunctionalUtilities, output = "", level = 0): string {
  if (elem.vchildren) {
    let childOutput: string[] = [];

    utils.forEach(elem.vchildren, (child) => {
      childOutput.push(vnodeToSource(child, utils, output, level + 1));
    });

    output += childOutput.join("\n");
  }

  let indent = "";
  for (let i = 0; i < level; i++) {
    indent += "  ";
  }

  if (elem.vtag) {
    let attrs: string[] = [];

    if (elem.vattrs) {
      const vattrs = elem.vattrs;
        attrs = Object.keys(vattrs)
          .reduce(
            (previousValue, key): string[] => {
              const attrVal = vattrs[key];
              let attrString: string;

              switch (typeof attrVal) {
              case ("boolean"):
                attrString = key;
                break;
              case ("number"):
              case ("string"):
                attrString = `${ key }="${ attrVal }"`;
                break;
              default:
                attrString = `${ key }={ ${ attrVal.toString() } }`;
              }

              return [...previousValue, attrString];
            }, attrs);
    }

    const attrsString = attrs.length > 0 ? ` ${ attrs.join(" ") }` : "";

    if (elem.vchildren) {
      output = `${ indent }<${ elem.vtag }${ attrsString }>\n${ output }\n${ indent }</${ elem.vtag }>`;
    } else {
      output = `${ indent }<${ elem.vtag }${ attrsString } />`
    }

  } else if (elem.vtext) {
    output = `${ indent }${ elem.vtext }`;
  }

  return output;
}

const AsSource: FunctionalComponent = (_, children, utils) => {
  var codeOut = "";

  utils.forEach(children, (child) => {
    codeOut += vnodeToSource(child, utils);
  });

  return <div>
    { children }
    <code class="html">{ codeOut }</code>
  </div>
};

export default AsSource;

Hmm, yes it should! It's recursing through the vdom hierarchy and inserting line breaks / indentation as needed https://gist.github.com/maxjustus/6dc3657370d615bcc70190c43161ec65#file-as-source-tsx-L11

If you view the source for that rendered output do you see linebreaks/indentation by chance?