Replace require() with library symbols in EXPORT_ES6 library files

Library functions run in synchronous context where await is unavailable.
Define top-level library symbols that use await import() at module init
time, then reference them via __deps from synchronous functions.

- Add libnode_imports.js with shared $nodeOs symbol, register in
  modules.mjs when EXPORT_ES6 is enabled.
- libatomic.js, libwasm_worker.js: Use $nodeOs for os.cpus().length
  instead of require('node:os').
- libwasi.js: Define $nodeCrypto for crypto.randomFillSync in
  $initRandomFill. Combine conditional __deps to avoid override.
- libcore.js: Define $nodeChildProcess for _emscripten_system.
- libnodepath.js: Switch $nodePath initializer to await import().
- libsockfs.js: Define $nodeWs ((await import('ws')).default) for
  WebSocket constructor in connect() and Server in listen().

Author: Bartek Wrona

src/lib/libatomic.js

@@ -159,9 +159,12 @@ addToLibrary({
 
   emscripten_has_threading_support: () => !!globalThis.SharedArrayBuffer,
 
+#if ENVIRONMENT_MAY_BE_NODE
+  emscripten_num_logical_cores__deps: ['$nodeOs'],
+#endif
   emscripten_num_logical_cores: () =>
 #if ENVIRONMENT_MAY_BE_NODE
-    ENVIRONMENT_IS_NODE ? require('node:os').cpus().length :
+    ENVIRONMENT_IS_NODE ? nodeOs.cpus().length :
 #endif
     navigator['hardwareConcurrency'],
 });

src/lib/libcore.js

@@ -343,6 +343,11 @@ addToLibrary({
   },
 #endif
 
+#if ENVIRONMENT_MAY_BE_NODE
+  $nodeOs: "ENVIRONMENT_IS_NODE ? {{{ makeNodeImport('node:os') }}} : undefined",
+  $nodeChildProcess: "ENVIRONMENT_IS_NODE ? {{{ makeNodeImport('node:child_process') }}} : undefined",
+  _emscripten_system__deps: ['$nodeChildProcess'],
+#endif
   _emscripten_system: (command) => {
 #if ENVIRONMENT_MAY_BE_NODE
     if (ENVIRONMENT_IS_NODE) {

src/lib/libnodepath.js

@@ -12,7 +12,7 @@
 // operations. Hence, using `nodePath` should be safe here.
 
 addToLibrary({
-  $nodePath: "require('node:path')",
+  $nodePath: "{{{ makeNodeImport('node:path') }}}",
   $PATH__deps: ['$nodePath'],
   $PATH: `{
     isAbs: nodePath.isAbsolute,

src/lib/libsockfs.js

@@ -5,10 +5,19 @@
  */
 
 addToLibrary({
+#if ENVIRONMENT_MAY_BE_NODE
+#if EXPORT_ES6
+  $nodeWs: "ENVIRONMENT_IS_NODE ? ({{{ makeNodeImport('ws') }}}).default : undefined",
+#else
+  $nodeWs: "ENVIRONMENT_IS_NODE ? {{{ makeNodeImport('ws') }}} : undefined",
+#endif
+  $SOCKFS__deps: ['$FS', '$nodeWs'],
+#else
+  $SOCKFS__deps: ['$FS'],
+#endif
   $SOCKFS__postset: () => {
     addAtInit('SOCKFS.root = FS.mount(SOCKFS, {}, null);');
   },
-  $SOCKFS__deps: ['$FS'],
   $SOCKFS: {
 #if expectToReceiveOnModule('websocket')
     websocketArgs: {},
@@ -216,7 +225,7 @@ addToLibrary({
             var WebSocketConstructor;
 #if ENVIRONMENT_MAY_BE_NODE
             if (ENVIRONMENT_IS_NODE) {
-              WebSocketConstructor = /** @type{(typeof WebSocket)} */(require('ws'));
+              WebSocketConstructor = /** @type{(typeof WebSocket)} */(nodeWs);
             } else
 #endif // ENVIRONMENT_MAY_BE_NODE
             {
@@ -522,7 +531,7 @@ addToLibrary({
         if (sock.server) {
            throw new FS.ErrnoError({{{ cDefs.EINVAL }}});  // already listening
         }
-        var WebSocketServer = require('ws').Server;
+        var WebSocketServer = nodeWs.Server;
         var host = sock.saddr;
 #if SOCKET_DEBUG
         dbg(`websocket: listen: ${host}:${sock.sport}`);

src/lib/libwasi.js

@@ -569,14 +569,21 @@ var WasiLibrary = {
 
   // random.h
 
-#if ENVIRONMENT_MAY_BE_SHELL
+#if ENVIRONMENT_MAY_BE_NODE && MIN_NODE_VERSION < 190000
+  $nodeCrypto: "ENVIRONMENT_IS_NODE ? {{{ makeNodeImport('node:crypto') }}} : undefined",
+#endif
+
+#if ENVIRONMENT_MAY_BE_SHELL && ENVIRONMENT_MAY_BE_NODE && MIN_NODE_VERSION < 190000
+  $initRandomFill__deps: ['$base64Decode', '$nodeCrypto'],
+#elif ENVIRONMENT_MAY_BE_SHELL
   $initRandomFill__deps: ['$base64Decode'],
+#elif ENVIRONMENT_MAY_BE_NODE && MIN_NODE_VERSION < 190000
+  $initRandomFill__deps: ['$nodeCrypto'],
 #endif
   $initRandomFill: () => {
 #if ENVIRONMENT_MAY_BE_NODE && MIN_NODE_VERSION < 190000
     // This block is not needed on v19+ since crypto.getRandomValues is builtin
     if (ENVIRONMENT_IS_NODE) {
-      var nodeCrypto = require('node:crypto');
       return (view) => nodeCrypto.randomFillSync(view);
     }
 #endif // ENVIRONMENT_MAY_BE_NODE

src/lib/libwasm_worker.js

@@ -289,9 +289,12 @@ if (ENVIRONMENT_IS_WASM_WORKER
     _wasmWorkers[id].postMessage({'_wsc': funcPtr, 'x': readEmAsmArgs(sigPtr, varargs) });
   },
 
+#if ENVIRONMENT_MAY_BE_NODE
+  emscripten_navigator_hardware_concurrency__deps: ['$nodeOs'],
+#endif
   emscripten_navigator_hardware_concurrency: () => {
 #if ENVIRONMENT_MAY_BE_NODE
-    if (ENVIRONMENT_IS_NODE) return require('node:os').cpus().length;
+    if (ENVIRONMENT_IS_NODE) return nodeOs.cpus().length;
 #endif
     return navigator['hardwareConcurrency'];
   },