electron-vue-viteのメインプロセスでesmoduleのみ対応のパッケージを使うときに必要なコンフィグ。

vite.config.ts

import { rmSync } from "node:fs";
import { defineConfig } from "vite";
import vue from "@vitejs/plugin-vue";
import electron, {
  Configuration as ElectronConfig,
} from "vite-plugin-electron";
import renderer from "vite-plugin-electron-renderer";
import pkg from "./package.json";
import esmodule from "vite-plugin-esmodule";
// https://vitejs.dev/config/
export default defineConfig(({ command }) => {
  rmSync("dist-electron", { recursive: true, force: true });
  const isServe = command === "serve";
  const isBuild = command === "build";
  const sourcemap = isServe || !!process.env.VSCODE_DEBUG;
  const esmodules = (() => {
    let packages: string[] = [];
    const plugin = esmodule((esms) => {
      packages = esms.filter((esm) => !(esm in pkg.devDependencies));
      return packages;
    });
    return { plugin, packages };
  })();
  const electronBaseConfig: ElectronConfig = {
    vite: {
      plugins: [esmodules.plugin],
      build: {
        minify: isBuild,
        rollupOptions: {
          external: Object.keys(
            "dependencies" in pkg ? pkg.dependencies : {}
          ).filter((pkg) => !esmodules.packages.includes(pkg)),
        },
      },
    },
  };
  const electronConfig: {
    mainProcess: ElectronConfig;
    preload: ElectronConfig;
  } = {
    mainProcess: {
      ...electronBaseConfig,
      entry: "electron/main/index.ts",
      onstart(options) {
        if (process.env.VSCODE_DEBUG) {
          console.log(
            /* For `.vscode/.debug.script.mjs` */ "[startup] Electron App"
          );
        } else {
          options.startup();
        }
      },
      vite: {
        ...electronBaseConfig.vite,
        build: {
          ...electronBaseConfig.vite.build,
          sourcemap,
          outDir: "dist-electron/main",
        },
      },
    },
    preload: {
      ...electronBaseConfig,
      entry: "electron/preload/index.ts",
      onstart(options) {
        options.reload();
      },
      vite: {
        ...electronBaseConfig.vite,
        build: {
          ...electronBaseConfig.vite.build,
          sourcemap: sourcemap ? "inline" : undefined, // #332
          outDir: "dist-electron/preload",
        },
      },
    },
  };
  return {
    plugins: [vue(), electron(Object.values(electronConfig)), renderer()],
    server:
      process.env.VSCODE_DEBUG &&
      (() => {
        const url = new URL(pkg.debug.env.VITE_DEV_SERVER_URL);
        return {
          host: url.hostname,
          port: +url.port,
        };
      })(),
    clearScreen: false,
  };
});