Monaco editor load theme without instance

Question

I’m creating a web application which uses Monaco Editor. Because this is already loaded, I decided to also use Monaco for syntax highlighting of static code blocks.

Based on this answer, I managed to add syntax highlighting to static code blocks (the elements and class names are added.

The problem is, the related CSS is only loaded if a Monaco editor instance is created, which happens on a different page. This means that it only works if a page that contains a Monaco editor instance.

I use the following React component to add syntax highlighting.

import { editor } from 'monaco-editor';
import React, { ReactElement, useEffect, useRef } from 'react';

interface CodeBlockProps {
  /**
   * The code to render.
   */
  code: string;

  /**
   * The language to use for highlighting the code.
   */
  language: string;
}

/**
 * Render a code block using syntax highlighting based on Monaco editor.
 */
export default function CodeBlock({ code, language }: CodeBlockProps): ReactElement {
  const ref = useRef<HTMLPreElement>();

  useEffect(() => {
    if (language) {
      editor.colorizeElement(ref.current, { theme: 'vs' });
    }
  }, [language]);

  return (
    <pre ref={ref} data-lang={language}>
      {code}
    </pre>
  );
}

How do I make Monaco load the CSS without creating an editor instance?

Answer 1

Inspired by this issue report: https://github.com/microsoft/monaco-editor/issues/1828

I did it like this:

import React from 'react';
import * as MonacoEditorApi from 'monaco-editor/esm/vs/editor/editor.api';
const { StaticServices } = require('monaco-editor/esm/vs/editor/standalone/browser/standaloneServices');
const { StandaloneThemeServiceImpl } = require('monaco-editor/esm/vs/editor/standalone/browser/standaloneThemeServiceImpl');

export const Viewer: React.FC<{ source: string }> = (props) => {
  // use a callback ref to get notified when the element has mounted
  const viewerRef = (ref: HTMLPreElement) => {
    if (ref) {
      MonacoEditorApi.editor.colorizeElement(ref, { theme: 'vs' });
      const themeService: typeof StandaloneThemeServiceImpl = StaticServices.standaloneThemeService.get();
      themeService.registerEditorContainer(ref);
    }
  };
  return (
    <pre data-lang="yaml" ref={viewerRef}>
      {props.source}
    </pre>
  );
};