vite.config.js

import { defineConfig } from "vite";
import { viteStaticCopy } from "vite-plugin-static-copy";

const cesiumSource = "node_modules/@cesium/engine";

// This is the base url for static files that CesiumJS needs to load.
// Set to an empty string to place the files at the site's root path
const cesiumBaseUrl = "cesiumStatic";

// https://vitejs.dev/config/
export default defineConfig({
  base: "",
  build: {
    rolldownOptions: {
      output: {
        manualChunks: (id) => {
          if (id.includes('@cesium/engine')) {
            return 'cesium';
          }
          if (id.includes('data/countries.json')) {
            return 'countries';
          }
        },
      },
    },
  },
  define: {
    // Define relative base path in cesium for loading assets
    // https://vitejs.dev/config/shared-options.html#define
    CESIUM_BASE_URL: `"${cesiumBaseUrl}"`,
  },
  plugins: [
    // Copy Cesium Assets, Widgets, and Workers to a static directory.
    // If you need to add your own static files to your project, use the `public` directory
    // and other options listed here: https://vitejs.dev/guide/assets.html#the-public-directory
    viteStaticCopy({
      targets: [
        { src: 'models', dest: '' },
        { src: 'images', dest: '' },
        { src: 'fonts', dest: '' },
        { src: `${cesiumSource}/Build/ThirdParty`, dest: `${cesiumBaseUrl}`, rename: { stripBase: 4 } },
        { src: `${cesiumSource}/Build/Workers`, dest: `${cesiumBaseUrl}`, rename: { stripBase: 4 } },
        { src: `${cesiumSource}/Source/Assets`, dest: `${cesiumBaseUrl}`, rename: { stripBase: 4 } },
        { src: `${cesiumSource}/Source/Widget`, dest: `${cesiumBaseUrl}`, rename: { stripBase: 4 } },
      ],
    }),
  ],
});