diff --git a/types/emscripten/emscripten-tests.ts b/types/emscripten/emscripten-tests.ts
index 06f7c5e43690a5d..03c1863241755f0 100644
--- a/types/emscripten/emscripten-tests.ts
+++ b/types/emscripten/emscripten-tests.ts
@@ -71,12 +71,18 @@ function FSTest(): void {
     FS.init(null, null, null);
 
     FS.mkdir("/working");
+    FS.mkdirTree("/nested/directory/structure");
+    FS.mkdirTree("/another/path", parseInt("0755", 8));
     FS.mount(NODEFS, { root: "." }, "/working");
 
     function myAppStartup(): void {
         FS.mkdir("/data");
         FS.mount(IDBFS, {}, "/data");
 
+        // Test isMountpoint - checks if a node is a mount point
+        const testNode = FS.lookupPath("/data", {}).node;
+        const isMount: boolean = FS.isMountpoint(testNode);
+
         FS.syncfs(true, (err) => {
             // handle callback
         });
@@ -92,6 +98,12 @@ function FSTest(): void {
     FS.registerDevice(id, {});
     FS.mkdev("/dummy", id);
 
+    // Test createDevice - creates a device with input/output functions
+    const inputDevice = FS.createDevice("/", "stdin", () => 65, undefined); // Returns 'A' (65)
+    const outputDevice = FS.createDevice("/", "stdout", undefined, (c: number) => console.log(String.fromCharCode(c)));
+    const bothDevice = FS.createDevice("/", "console", () => 66, (c: number) => console.log(c)); // Returns 'B' (66)
+    const simpleDevice = FS.createDevice("/", "null");
+
     FS.writeFile("file", "foobar");
     FS.symlink("file", "link");
 
@@ -119,7 +131,19 @@ function FSTest(): void {
     const data = new Uint8Array(32);
     const wstream = FS.open("dummy1", "w+");
     FS.write(wstream, data, 0, data.length, 0);
-    FS.close(wstream);
+
+    // Test FS.open with numeric flags
+    const numericWriteStream = FS.open("numeric-write-stream-test", 1);
+    FS.write(numericWriteStream, data, 0, data.length, 0);
+    FS.close(numericWriteStream);
+
+    // Test getStream - gets stream by file descriptor
+    const streamFromFD = FS.getStream(wstream.fd!);
+    // $ExpectType FSStream
+    streamFromFD;
+
+    // Test closeStream - closes stream by file descriptor
+    FS.closeStream(wstream.fd!);
 
     FS.createDataFile("/", "dummy2", data, true, true, true);
 
diff --git a/types/emscripten/index.d.ts b/types/emscripten/index.d.ts
index 0b9ab6b90d8e100..17d83f5a52453d5 100644
--- a/types/emscripten/index.d.ts
+++ b/types/emscripten/index.d.ts
@@ -268,6 +268,12 @@ declare namespace FS {
     function makedev(ma: number, mi: number): number;
     function registerDevice(dev: number, ops: Partial<StreamOps>): void;
     function getDevice(dev: number): { stream_ops: StreamOps };
+    function createDevice(
+        parent: string | FSNode,
+        name: string,
+        input?: () => number | null | undefined,
+        output?: (c: number) => any,
+    ): FSNode;
 
     //
     // core
@@ -277,8 +283,13 @@ declare namespace FS {
     function syncfs(callback: (e: any) => any, populate?: boolean): void;
     function mount(type: Emscripten.FileSystemType, opts: any, mountpoint: string): any;
     function unmount(mountpoint: string): void;
+    function isMountpoint(node: FSNode): boolean;
+
+    function closeStream(fd: number): void;
+    function getStream(fd: number): FSStream;
 
     function mkdir(path: string, mode?: number): FSNode;
+    function mkdirTree(path: string, mode?: number): void;
     function mkdev(path: string, mode?: number, dev?: number): FSNode;
     function symlink(oldpath: string, newpath: string): FSNode;
     function rename(old_path: string, new_path: string): void;
@@ -297,7 +308,7 @@ declare namespace FS {
     function truncate(path: string, len: number): void;
     function ftruncate(fd: number, len: number): void;
     function utime(path: string, atime: number, mtime: number): void;
-    function open(path: string, flags: string, mode?: number, fd_start?: number, fd_end?: number): FSStream;
+    function open(path: string, flags: string | number, mode?: number): FSStream;
     function close(stream: FSStream): void;
     function llseek(stream: FSStream, offset: number, whence: number): number;
     function read(stream: FSStream, buffer: ArrayBufferView, offset: number, length: number, position?: number): number;
@@ -309,7 +320,6 @@ declare namespace FS {
         position?: number,
         canOwn?: boolean,
     ): number;
-    function allocate(stream: FSStream, offset: number, length: number): void;
     function mmap(
         stream: FSStream,
         buffer: ArrayBufferView,