[NODERAWFS] Move filesystem wrapping to __postset (emscripten-core#22559)

Resolves: emscripten-core#22553.

Author: kleisauke

src/library_noderawfs.js

@@ -10,35 +10,27 @@ addToLibrary({
     if (!ENVIRONMENT_IS_NODE) {
       throw new Error("NODERAWFS is currently only supported on Node.js environment.")
     }
-    // Use this to reference our in-memory filesystem
-    var VFS = Object.assign({}, FS);
-    // Override the init function with our own
-    FS.init = NODERAWFS.init;`,
-  $NODERAWFS: {
-    init() {
-      var _wrapNodeError = function(func) {
-        return function(...args) {
-          try {
-            return func(...args)
-          } catch (e) {
-            if (e.code) {
-              throw new FS.ErrnoError(ERRNO_CODES[e.code]);
-            }
-            throw e;
+    var _wrapNodeError = function(func) {
+      return function(...args) {
+        try {
+          return func(...args)
+        } catch (e) {
+          if (e.code) {
+            throw new FS.ErrnoError(ERRNO_CODES[e.code]);
           }
+          throw e;
         }
-      };
-
-      // Wrap the whole in-memory filesystem API with
-      // our Node.js based functions
-      for (var _key in NODERAWFS) {
-        /** @suppress {partialAlias} */
-        FS[_key] = _wrapNodeError(NODERAWFS[_key]);
       }
-
-      // Setup the stdin, stdout and stderr devices
-      FS.createStandardStreams();
-    },
+    };
+    // Use this to reference our in-memory filesystem
+    /** @suppress {partialAlias} */
+    var VFS = Object.assign({}, FS);
+    // Wrap the whole in-memory filesystem API with
+    // our Node.js based functions
+    for (var _key in NODERAWFS) {
+      FS[_key] = _wrapNodeError(NODERAWFS[_key]);
+    }`,
+  $NODERAWFS: {
     lookup(parent, name) {
 #if ASSERTIONS
       assert(parent)

test/test_other.py

@@ -9753,6 +9753,11 @@ def test_noderawfs_access_abspath(self):
     self.run_process([EMCC, 'access.c', '-sNODERAWFS'])
     self.run_js('a.out.js', args=[os.path.abspath('foo')])
 
+  def test_noderawfs_readfile_prerun(self):
+    create_file('foo', 'bar')
+    self.add_pre_run("console.log(FS.readFile('foo', { encoding: 'utf8' }));")
+    self.do_runf('hello_world.c', 'bar', emcc_args=['-sNODERAWFS', '-sFORCE_FILESYSTEM'])
+
   @disabled('https://github.com/nodejs/node/issues/18265')
   def test_node_code_caching(self):
     self.run_process([EMCC, test_file('hello_world.c'),