esbuild

npm install esbuild esbuild-sass-plugin --save-dev

npm install @wordpress/blocks @wordpress/element

package.json

{
  "name": "twentyfive-child",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "build": "node build.js",
    "start": "node build.js --watch",
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "esbuild": "^0.24.2",
    "esbuild-sass-plugin": "^3.3.1"
  },
  "dependencies": {
    "@wordpress/blocks": "^14.3.0",
    "@wordpress/element": "^6.14.0"
  }
}

build.js

const esbuild = require('esbuild');

(async () => {
  const ctx = await esbuild.context({
    entryPoints: ['src/index.js'],
    bundle: true,
    minify: true,
    sourcemap: false,
    outfile: 'dist/bundle.js',
    target: ['es2015'],
    loader: { '.js': 'jsx' },
  });

  await ctx.watch();
  console.log('Watching for changes...');
})();