babel-plugin-jsx/packages/jsx-explorer/src/index.js

import * as monaco from 'monaco-editor';
import { transform } from '@babel/core';
import babelPluginJSx from '../../babel-plugin-jsx/src';
import './index.css';
// or import * as monaco from 'monaco-editor/esm/vs/editor/editor.api';
// if shipping only a subset of the features & languages is desired

if (module.hot) {
  module.hot.accept('../../babel-plugin-jsx/src', () => {
    compile();
  });
}

const sharedEditorOptions = {
  theme: 'vs-dark',
  fontSize: 14,
  wordWrap: 'on',
  scrollBeyondLastLine: false,
  renderWhitespace: 'selection',
  contextmenu: false,
  minimap: {
    enabled: false,
  },
};

monaco.languages.typescript.typescriptDefaults.setCompilerOptions({
  allowJs: true,
  allowNonTsExtensions: true,
  lib: [],
  jsx: monaco.languages.typescript.JsxEmit.React,
  target: monaco.languages.typescript.ScriptTarget.Latest,
  typeRoots: ['node_modules/@types'],
});

const editor = monaco.editor.create(document.getElementById('source'), {
  value: localStorage.getItem('state') || 'const App = () => <div>Hello World</div>',
  language: 'javascript',
  tabSize: 2,
  ...sharedEditorOptions,
});

const output = monaco.editor.create(document.getElementById('output'), {
  value: '',
  language: 'javascript',
  readOnly: true,
  tabSize: 2,
  ...sharedEditorOptions,
});

const compile = () => {
  const src = editor.getValue();
  localStorage.setItem('state', src);
  transform(src, {
    babelrc: false,
    plugins: [babelPluginJSx],
  }, (err, result) => {
    if (!err) {
      output.setValue(result.code);
    } else {
      output.setValue(err.message);
    }
  });
};

// handle resize
window.addEventListener('resize', () => {
  editor.layout();
  output.layout();
});

compile();

// update compile output when input changes
editor.onDidChangeModelContent(debounce(compile));


function debounce(fn, delay = 300) {
  let prevTimer = null;
  return ((...args) => {
    if (prevTimer) {
      clearTimeout(prevTimer);
    }
    prevTimer = window.setTimeout(() => {
      fn(...args);
      prevTimer = null;
    }, delay);
  });
}