diff --git a/src/library_fs.js b/src/library_fs.js
index a794718499788..bbc0dd987ab7f 100644
--- a/src/library_fs.js
+++ b/src/library_fs.js
@@ -1378,7 +1378,7 @@ FS.staticInit();
       FS.mkdir('/proc/self/fd');
       FS.mount({
         mount() {
-          var node = FS.createNode(proc_self, 'fd', {{{ cDefs.S_IFDIR }}} | {{{ 0777 }}}, {{{ cDefs.S_IXUGO }}});
+          var node = FS.createNode(proc_self, 'fd', {{{ cDefs.S_IFDIR | 0o777 }}}, {{{ cDefs.S_IXUGO }}});
           node.node_ops = {
             lookup(parent, name) {
               var fd = +name;
diff --git a/src/library_lz4.js b/src/library_lz4.js
index 83307075a6c19..061af9faf72a7 100644
--- a/src/library_lz4.js
+++ b/src/library_lz4.js
@@ -8,8 +8,8 @@
 addToLibrary({
   $LZ4__deps: ['$FS', '$preloadPlugins'],
   $LZ4: {
-    DIR_MODE: {{{ cDefs.S_IFDIR }}} | 511 /* 0777 */,
-    FILE_MODE: {{{ cDefs.S_IFREG }}} | 511 /* 0777 */,
+    DIR_MODE: {{{ cDefs.S_IFDIR | 0o777 }}},
+    FILE_MODE: {{{ cDefs.S_IFREG | 0o777 }}},
     CHUNK_SIZE: -1,
     codec: null,
     init() {
diff --git a/src/library_memfs.js b/src/library_memfs.js
index b6a87935c3c2a..b4beccd08aadf 100644
--- a/src/library_memfs.js
+++ b/src/library_memfs.js
@@ -18,7 +18,7 @@ addToLibrary({
   $MEMFS: {
     ops_table: null,
     mount(mount) {
-      return MEMFS.createNode(null, '/', {{{ cDefs.S_IFDIR }}} | 511 /* 0777 */, 0);
+      return MEMFS.createNode(null, '/', {{{ cDefs.S_IFDIR | 0o777 }}}, 0);
     },
     createNode(parent, name, mode, dev) {
       if (FS.isBlkdev(mode) || FS.isFIFO(mode)) {
@@ -232,7 +232,7 @@ addToLibrary({
         return entries;
       },
       symlink(parent, newname, oldpath) {
-        var node = MEMFS.createNode(parent, newname, 511 /* 0777 */ | {{{ cDefs.S_IFLNK }}}, 0);
+        var node = MEMFS.createNode(parent, newname, 0o777 | {{{ cDefs.S_IFLNK }}}, 0);
         node.link = oldpath;
         return node;
       },
diff --git a/src/library_pipefs.js b/src/library_pipefs.js
index 430cf40d5fd71..88a0ededa9c8d 100644
--- a/src/library_pipefs.js
+++ b/src/library_pipefs.js
@@ -12,7 +12,7 @@ addToLibrary({
     mount(mount) {
       // Do not pollute the real root directory or its child nodes with pipes
       // Looks like it is OK to create another pseudo-root node not linked to the FS.root hierarchy this way
-      return FS.createNode(null, '/', {{{ cDefs.S_IFDIR }}} | 511 /* 0777 */, 0);
+      return FS.createNode(null, '/', {{{ cDefs.S_IFDIR }}} | 0o777, 0);
     },
     createPipe() {
       var pipe = {
diff --git a/src/library_sockfs.js b/src/library_sockfs.js
index 4d22a81bcc820..e5c1b8674c883 100644
--- a/src/library_sockfs.js
+++ b/src/library_sockfs.js
@@ -41,7 +41,7 @@ addToLibrary({
       SOCKFS.on('close', (fd) => dbg(`websocket: close fd = ${fd}`));
 #endif
 
-      return FS.createNode(null, '/', {{{ cDefs.S_IFDIR }}} | 511 /* 0777 */, 0);
+      return FS.createNode(null, '/', {{{ cDefs.S_IFDIR | 0o777 }}}, 0);
     },
     createSocket(family, type, protocol) {
       type &= ~{{{ cDefs.SOCK_CLOEXEC | cDefs.SOCK_NONBLOCK }}}; // Some applications may pass it; it makes no sense for a single process.
diff --git a/src/library_wasmfs.js b/src/library_wasmfs.js
index b209d4be9ec98..645f3ac597342 100644
--- a/src/library_wasmfs.js
+++ b/src/library_wasmfs.js
@@ -178,9 +178,8 @@ FS.init();
     rmdir: (path) => FS.handleError(
       withStackSave(() => __wasmfs_rmdir(stringToUTF8OnStack(path)))
     ),
-    open: (path, flags, mode) => withStackSave(() => {
+    open: (path, flags, mode = 0o666) => withStackSave(() => {
       flags = typeof flags == 'string' ? FS_modeStringToFlags(flags) : flags;
-      mode = typeof mode == 'undefined' ? 438 /* 0666 */ : mode;
       var buffer = stringToUTF8OnStack(path);
       var fd = FS.handleError(__wasmfs_open(buffer, flags, mode));
       return { fd : fd };
@@ -449,7 +448,7 @@ FS.init();
     mkdev(path, mode, dev) {
       if (typeof dev === 'undefined') {
         dev = mode;
-        mode = 438 /* 0666 */;
+        mode = 0o666;
       }
 
       var deviceBackend = wasmFSDevices[dev];
@@ -517,7 +516,7 @@ FS.init();
 
   $FS_create__deps: ['$FS_mknod'],
   // Default settings copied from the legacy JS FS API.
-  $FS_create: (path, mode = 438 /* 0666 */) => {
+  $FS_create: (path, mode = 0o666) => {
     mode &= {{{ cDefs.S_IALLUGO }}};
     mode |= {{{ cDefs.S_IFREG }}};
     return FS_mknod(path, mode, 0);
@@ -546,7 +545,7 @@ FS.init();
   },
 
   $FS_mkdir__deps: ['_wasmfs_mkdir'],
-  $FS_mkdir: (path, mode = 511 /* 0777 */) => FS.handleError(withStackSave(() => {
+  $FS_mkdir: (path, mode = 0o777) => FS.handleError(withStackSave(() => {
     var buffer = stringToUTF8OnStack(path);
     return __wasmfs_mkdir(buffer, mode);
   })),
diff --git a/src/library_workerfs.js b/src/library_workerfs.js
index cc5e5a7117962..28020bfac7e4d 100644
--- a/src/library_workerfs.js
+++ b/src/library_workerfs.js
@@ -7,8 +7,8 @@
 addToLibrary({
   $WORKERFS__deps: ['$FS'],
   $WORKERFS: {
-    DIR_MODE: {{{ cDefs.S_IFDIR }}} | 511 /* 0777 */,
-    FILE_MODE: {{{ cDefs.S_IFREG }}} | 511 /* 0777 */,
+    DIR_MODE: {{{ cDefs.S_IFDIR | 0o777 }}},
+    FILE_MODE: {{{ cDefs.S_IFREG | 0o777 }}},
     reader: null,
     mount(mount) {
       assert(ENVIRONMENT_IS_WORKER);