refactor(core): using import defer

.prettierrc

@@ -1,3 +1,4 @@
 {
-  "singleQuote": true
+  "singleQuote": true,
+  "plugins": ["@prettier/plugin-oxc"]
 }

package.json

@@ -15,7 +15,7 @@
     "e2e:rspack": "cd ./e2e && pnpm e2e:rspack",
     "e2e:webpack": "cd ./e2e && pnpm e2e:webpack",
     "format": "prettier --experimental-cli --write . && heading-case --write",
-    "lint": "biome check && pnpm lint:type",
+    "lint": "biome check",
     "lint:type": "rslint",
     "prebundle": "nx run-many -t prebundle",
     "prepare": "simple-git-hooks && pnpm build",
@@ -35,6 +35,7 @@
   },
   "devDependencies": {
     "@biomejs/biome": "^2.3.2",
+    "@prettier/plugin-oxc": "^0.0.4",
     "@rsbuild/config": "workspace:*",
     "@rslint/core": "^0.1.13",
     "@rstest/core": "^0.6.1",

packages/compat/plugin-webpack-swc/package.json

@@ -38,7 +38,7 @@
   "devDependencies": {
     "@rsbuild/core": "workspace:*",
     "@rsbuild/webpack": "workspace:*",
-    "@rslib/core": "0.17.0",
+    "@rslib/core": "0.17.1",
     "@types/lodash": "^4.17.20",
     "@types/semver": "^7.7.1",
     "typescript": "^5.9.3",

packages/compat/webpack/package.json

@@ -38,7 +38,7 @@
   },
   "devDependencies": {
     "@rsbuild/core": "workspace:*",
-    "@rslib/core": "0.17.0",
+    "@rslib/core": "0.17.1",
     "@scripts/test-helper": "workspace:*",
     "@types/node": "^24.9.2",
     "ansi-escapes": "4.3.2",

packages/core/package.json

@@ -61,7 +61,7 @@
   "devDependencies": {
     "@jridgewell/remapping": "^2.3.5",
     "@jridgewell/trace-mapping": "^0.3.31",
-    "@rslib/core": "0.17.0",
+    "@rslib/core": "0.17.1",
     "@types/connect": "3.4.38",
     "@types/cors": "^2.8.19",
     "@types/node": "^24.9.2",

packages/core/rslib.config.ts

@@ -162,4 +162,11 @@ export default defineConfig({
       },
     },
   ],
+  tools: {
+    rspack: {
+      experiments: {
+        deferImport: true,
+      },
+    },
+  },
 });

packages/core/src/createContext.ts

@@ -100,7 +100,7 @@ export async function updateEnvironmentContext(
     const { entry = {}, tsconfigPath } = config.source;
     const htmlPaths = getEnvironmentHTMLPaths(entry, config);
     const webSocketToken =
-      context.action === 'dev' ? await hash(context.rootPath + name) : '';
+      context.action === 'dev' ? hash(context.rootPath + name) : '';
 
     const environmentContext: EnvironmentContext = {
       index,

packages/core/src/helpers/exitHook.ts

@@ -1,5 +1,5 @@
-import { constants } from 'node:os';
-import process from 'node:process';
+import defer * as os from 'node:os';
+import defer * as process from 'node:process';
 
 type Callback = (exitCode: number) => void;
 
@@ -37,11 +37,11 @@ export function exitHook(onExit: Callback): () => void {
     // Use `process.on` instead of `process.once` to disable
     // Node.js's default exit behavior
     process.on('SIGINT', () => {
-      exit(constants.signals.SIGINT + 128, 'SIGINT');
+      exit(os.constants.signals.SIGINT + 128, 'SIGINT');
     });
     // `kill` command
     process.once('SIGTERM', () => {
-      exit(constants.signals.SIGTERM + 128, 'SIGTERM');
+      exit(os.constants.signals.SIGTERM + 128, 'SIGTERM');
     });
     // process.exit or others
     process.once('exit', (exitCode) => {

packages/core/src/helpers/index.ts

@@ -1,3 +1,4 @@
+import defer * as crypto from 'node:crypto';
 import deepmerge from 'deepmerge';
 import RspackChain from '../../compiled/rspack-chain';
 import type {
@@ -209,8 +210,7 @@ export const isTTY = (type: 'stdin' | 'stdout' = 'stdout'): boolean => {
   );
 };
 
-export async function hash(data: string): Promise<string> {
-  const crypto = await import('node:crypto');
+export function hash(data: string): string {
   // Available in Node.js v20.12.0
   // faster than `crypto.createHash()` when hashing a smaller amount of data (<= 5MB)
   if (crypto.hash) {

packages/core/src/loadConfig.ts

@@ -1,6 +1,7 @@
 import fs from 'node:fs';
 import { isAbsolute, join } from 'node:path';
 import { pathToFileURL } from 'node:url';
+import defer * as jiti from 'jiti';
 import { __filename } from './constants';
 import { color, getNodeEnv, isObject } from './helpers';
 import { logger } from './logger';
@@ -167,8 +168,7 @@ export async function loadConfig({
 
   if (configExport === undefined) {
     try {
-      const { createJiti } = await import('jiti');
-      const jiti = createJiti(__filename, {
+      const instance = jiti.createJiti(__filename, {
         // disable require cache to support restart CLI and read the new config
         moduleCache: false,
         interopDefault: true,
@@ -177,9 +177,12 @@ export async function loadConfig({
         nativeModules: ['@rspack/core', 'typescript'],
       });
 
-      configExport = await jiti.import<RsbuildConfigExport>(configFilePath, {
-        default: true,
-      });
+      configExport = await instance.import<RsbuildConfigExport>(
+        configFilePath,
+        {
+          default: true,
+        },
+      );
     } catch (err) {
       logger.error(
         `Failed to load file with jiti: ${color.dim(configFilePath)}`,

packages/core/src/plugins/cache.ts

@@ -154,7 +154,7 @@ export const pluginCache = (): RsbuildPlugin => ({
 
       // set cache name to avoid cache conflicts between different environments
       const cacheVersion = useDigest
-        ? `${environment.name}-${env}-${await hash(JSON.stringify(cacheConfig.cacheDigest))}`
+        ? `${environment.name}-${env}-${hash(JSON.stringify(cacheConfig.cacheDigest))}`
         : `${environment.name}-${env}`;
 
       if (bundlerType === 'rspack') {

packages/core/src/plugins/fileSize.ts

@@ -5,7 +5,7 @@
 import fs from 'node:fs';
 import path from 'node:path';
 import { promisify } from 'node:util';
-import zlib from 'node:zlib';
+import defer * as zlib from 'node:zlib';
 import { JS_REGEX } from '../constants';
 import { color } from '../helpers';
 import { getAssetsFromStats, type RsbuildAsset } from '../helpers/stats';

packages/core/src/server/cliShortcuts.ts

@@ -1,3 +1,4 @@
+import defer * as readline from 'node:readline';
 import { color, isTTY } from '../helpers';
 import { logger } from '../logger';
 import type { CliShortcut, NormalizedConfig } from '../types/config';
@@ -78,8 +79,7 @@ export async function setupCliShortcuts({
     );
   }
 
-  const { createInterface } = await import('node:readline');
-  const rl = createInterface({
+  const rl = readline.createInterface({
     input: process.stdin,
   });
 

packages/core/src/server/devServer.ts

@@ -366,7 +366,7 @@ export async function createDevServer<
 
   const httpServer = middlewareMode
     ? null
-    : await createHttpServer({
+    : createHttpServer({
         serverConfig: config.server,
         middlewares,
       });

packages/core/src/server/gracefulShutdown.ts

@@ -1,4 +1,4 @@
-import { constants } from 'node:os';
+import defer * as os from 'node:os';
 
 /**
  * A set to store all cleanup callbacks that should be executed before process termination
@@ -41,7 +41,7 @@ export const setupGracefulShutdown = (): (() => void) => {
   // or manually via 'kill -15 <pid>' or 'kill -TERM <pid>' command.
   // Add 128 to signal number as per POSIX convention for signal-terminated processes.
   const onSigterm = () => {
-    handleTermination(constants.signals.SIGTERM + 128);
+    handleTermination(os.constants.signals.SIGTERM + 128);
   };
   process.once('SIGTERM', onSigterm);
 

packages/core/src/server/gzipMiddleware.ts

@@ -1,5 +1,5 @@
 import type { ServerResponse } from 'node:http';
-import zlib from 'node:zlib';
+import defer * as zlib from 'node:zlib';
 import type { CompressOptions, RequestHandler } from '../types';
 
 const ENCODING_REGEX = /\bgzip\b/;

packages/core/src/server/helper.ts

@@ -1,6 +1,7 @@
 import type { IncomingMessage, Server } from 'node:http';
 import type { Http2SecureServer } from 'node:http2';
 import type { Socket } from 'node:net';
+import defer * as net from 'node:net';
 import os from 'node:os';
 import { posix, relative, sep } from 'node:path';
 import { DEFAULT_DEV_HOST } from '../constants';
@@ -270,7 +271,6 @@ export const getPort = async ({
     tryLimits = 1;
   }
 
-  const { createServer } = await import('node:net');
   const original = port;
 
   let found = false;
@@ -279,7 +279,7 @@ export const getPort = async ({
   while (!found && attempts <= tryLimits) {
     try {
       await new Promise((resolve, reject) => {
-        const server = createServer();
+        const server = net.createServer();
         server.unref();
         server.on('error', reject);
         server.listen({ port, host }, () => {
@@ -379,13 +379,12 @@ const isLoopbackHost = (host: string) => {
   return loopbackHosts.has(host);
 };
 
-export const getHostInUrl = async (host: string): Promise<string> => {
+export const getHostInUrl = (host: string): string => {
   if (host === DEFAULT_DEV_HOST) {
     return 'localhost';
   }
 
-  const { isIPv6 } = await import('node:net');
-  if (isIPv6(host)) {
+  if (net.isIPv6(host)) {
     return host === '::' ? '[::1]' : `[${host}]`;
   }
   return host;
@@ -427,7 +426,7 @@ export const getAddressUrls = async ({
   if (host && host !== DEFAULT_DEV_HOST) {
     const url = concatUrl({
       port,
-      host: await getHostInUrl(host),
+      host: getHostInUrl(host),
       protocol,
     });
     return [

packages/core/src/server/hmrFallback.ts

@@ -1,3 +1,4 @@
+import defer * as dns from 'node:dns';
 import { isWildcardHost } from './helper';
 
 /**
@@ -8,10 +9,9 @@ import { isWildcardHost } from './helper';
  * This helps detect cases where IPv4/IPv6 resolution might vary.
  */
 async function getLocalhostResolvedAddress(): Promise<string | undefined> {
-  const { promises: dns } = await import('node:dns');
   const [defaultLookup, explicitLookup] = await Promise.all([
-    dns.lookup('localhost'),
-    dns.lookup('localhost', { verbatim: true }),
+    dns.promises.lookup('localhost'),
+    dns.promises.lookup('localhost', { verbatim: true }),
   ]);
   const match =
     defaultLookup.family === explicitLookup.family &&

packages/core/src/server/httpServer.ts

@@ -1,23 +1,24 @@
 import type { Server } from 'node:http';
+import defer * as http from 'node:http';
 import type { Http2SecureServer } from 'node:http2';
+import defer * as http2 from 'node:http2';
+import defer * as https from 'node:https';
 import type { Connect, ServerConfig } from '../types';
 
-export const createHttpServer = async ({
+export const createHttpServer = ({
   serverConfig,
   middlewares,
 }: {
   serverConfig: ServerConfig;
   middlewares: Connect.Server;
-}): Promise<Http2SecureServer | Server> => {
+}): Http2SecureServer | Server => {
   if (serverConfig.https) {
     // http-proxy does not supports http2
     if (serverConfig.proxy) {
-      const { createServer } = await import('node:https');
-      return createServer(serverConfig.https, middlewares);
+      return https.createServer(serverConfig.https, middlewares);
     }
 
-    const { createSecureServer } = await import('node:http2');
-    return createSecureServer(
+    return http2.createSecureServer(
       {
         allowHTTP1: true,
         // increase the maximum memory (MiB)
@@ -29,6 +30,5 @@ export const createHttpServer = async ({
     );
   }
 
-  const { createServer } = await import('node:http');
-  return createServer(middlewares);
+  return http.createServer(middlewares);
 };

packages/core/src/server/open.ts

@@ -1,3 +1,5 @@
+import defer * as childProcess from 'node:child_process';
+import defer * as nodeUtil from 'node:util';
 import { STATIC_PATH } from '../constants';
 import { castArray, color } from '../helpers';
 import { canParse } from '../helpers/url';
@@ -64,9 +66,7 @@ async function openBrowser(url: string): Promise<boolean> {
   // a Chromium browser with AppleScript. This lets us reuse an
   // existing tab when possible instead of creating a new one.
   if (shouldTryAppleScript(browser, browserArgs)) {
-    const { exec } = await import('node:child_process');
-    const { promisify } = await import('node:util');
-    const execAsync = promisify(exec);
+    const execAsync = nodeUtil.promisify(childProcess.exec);
 
     /**
      * Find the browser that is currently running
@@ -203,7 +203,7 @@ export async function open({
 
   const urls: string[] = [];
   const protocol = https ? 'https' : 'http';
-  const host = await getHostInUrl(config.server.host);
+  const host = getHostInUrl(config.server.host);
   const baseUrl = `${protocol}://${host}:${port}`;
 
   if (!targets.length) {

packages/core/src/server/prodServer.ts

@@ -1,5 +1,6 @@
 import type { Server } from 'node:http';
 import type { Http2SecureServer } from 'node:http2';
+import defer * as zlib from 'node:zlib';
 import { getPathnameFromUrl } from '../helpers/path';
 import { requireCompiledPackage } from '../helpers/vendors';
 import { isVerbose, logger } from '../logger';
@@ -104,11 +105,10 @@ export class RsbuildProdServer {
     // compression is placed after proxy middleware to avoid breaking SSE (Server-Sent Events),
     // but before other middlewares to ensure responses are properly compressed
     if (compress) {
-      const { constants } = await import('node:zlib');
       this.middlewares.use(
         gzipMiddleware({
           // simulates the common gzip compression rates
-          level: constants.Z_DEFAULT_COMPRESSION,
+          level: zlib.constants.Z_DEFAULT_COMPRESSION,
           ...(typeof compress === 'object' ? compress : undefined),
         }),
       );
@@ -201,7 +201,7 @@ export async function startProdServer(
 
   await context.hooks.onBeforeStartProdServer.callBatch();
 
-  const httpServer = await createHttpServer({
+  const httpServer = createHttpServer({
     serverConfig,
     middlewares: server.middlewares,
   });

packages/core/src/server/runner/asModule.ts

@@ -1,11 +1,12 @@
 import type { Module, ModuleLinker, SyntheticModule } from 'node:vm';
+import defer * as vm from 'node:vm';
 
 export const asModule = async (
   something: Record<string, any>,
   context: Record<string, any>,
   unlinked?: boolean,
 ): Promise<Module | SyntheticModule> => {
-  const { Module, SyntheticModule } = await import('node:vm');
+  const { Module, SyntheticModule } = vm;
 
   if (something instanceof Module) {
     return something;

packages/create-rsbuild/package.json

@@ -39,7 +39,7 @@
     "@rsbuild/plugin-solid": "workspace:*",
     "@rsbuild/plugin-svelte": "workspace:*",
     "@rsbuild/plugin-vue": "workspace:*",
-    "@rslib/core": "0.17.0",
+    "@rslib/core": "0.17.1",
     "@types/node": "^24.9.2",
     "typescript": "^5.9.3"
   },

packages/plugin-babel/package.json

@@ -40,7 +40,7 @@
   },
   "devDependencies": {
     "@rsbuild/core": "workspace:*",
-    "@rslib/core": "0.17.0",
+    "@rslib/core": "0.17.1",
     "@scripts/test-helper": "workspace:*",
     "@types/node": "^24.9.2",
     "babel-loader": "10.0.0",