@@ -19,7 +19,7 @@ clap = { version = "4", features = ["derive"] }
 tokio = { version = "1", default-features = false, features = ["rt", "macros"] }
 wasmtime = { version = "47", features = ["component-model", "async"] }
 wasmtime-wasi = { version = "47", default-features = false, features = ["p2", "p3"] }
-wit-parser = "0.256"
+wit-parser = "0.258"
 
 [package]
 name = "componentize-qjs-cli"
@@ -57,11 +57,11 @@ componentize-qjs.workspace = true
 anyhow.workspace = true
 clap.workspace = true
 tokio.workspace = true
-oxc_minifier = "0.144.0"
-oxc_allocator = "0.144.0"
-oxc_codegen = "0.144.0"
-oxc_parser = "0.144.0"
-oxc_span = "0.144.0"
+oxc_minifier = "0.147.0"
+oxc_allocator = "0.147.0"
+oxc_codegen = "0.147.0"
+oxc_parser = "0.147.0"
+oxc_span = "0.147.0"
 
 [features]
 default = ["component-model-async"]
 
@@ -197,6 +197,7 @@ a project root that contains shared files or `node_modules`.
 |----------|---------|---------|
 | `list<T>` | `Array` | `[1, 2, 3]` |
 | `list<u8>` | `Uint8Array` or `Array` | `new Uint8Array([1, 2, 3])` |
+| `map<K, V>` | `Map` | `new Map([["key", value]])` |
 | `tuple<T, U, ...>` | `Array` | `[42, "hello"]` |
 | `option<T>` | `T \| null` (nested: `{ tag: "some"\|"none", val }`) | `null` for none; `option<option<T>>` is wrapped |
 | `result<T, E>` | top-level function result: return `T` or throw `E`; nested result: `{ tag: "ok"\|"err", val?: T\|E }` | `return 42` / `throw "error"` |
 
@@ -37,14 +37,15 @@ bytes = "1"
 oxc_resolver = "11.21.0"
 tokio.workspace = true
 wit-parser.workspace = true
-wit-component = { version = "0.256", features = ["dummy-module"] }
-wit-dylib = "0.256"
+wit-component = { version = "0.258", features = ["dummy-module"] }
+wit-dylib = "0.258"
 wasi-preview1-component-adapter-provider = "47"
 wasmtime.workspace = true
 wasmtime-wasi.workspace = true
 wasmtime-wizer = { version = "47", features = ["component-model", "wasmtime"] }
-wac-graph = "0.10"
+wasm-compose = { version = "0.258", default-features = false }
 indexmap = "2"
+tempfile = "3"
 
 [build-dependencies]
 anyhow.workspace = true
 
@@ -283,6 +283,11 @@ fn typedef_const_name(resolve: &Resolve, id: TypeId, style: ConstNameStyle) -> S
         TypeDefKind::List(inner) => {
             format!("LIST_{}", type_const_name(resolve, Some(inner), style))
         }
+        TypeDefKind::Map(key, value) => {
+            let key = type_const_name(resolve, Some(key), style);
+            let value = type_const_name(resolve, Some(value), style);
+            format!("MAP_{key}_{value}")
+        }
         TypeDefKind::Future(inner) => {
             let inner = inner
                 .as_ref()
 
@@ -136,18 +136,20 @@ pub async fn componentize(opts: &ComponentizeOpts<'_>) -> Result<Vec<u8>> {
         wit_component::StringEncoding::UTF8,
     )?;
 
-    let pre_wizer_component = wit_component::Linker::default()
-        .validate(true)
-        .library(
-            "componentize_qjs_runtime.wasm",
-            runtime_wasm(opts.runtime),
-            false,
-        )?
-        .library("wit-dylib.wasm", &wit_dylib, false)?
-        .adapter(
-            "wasi_snapshot_preview1",
-            WASI_SNAPSHOT_PREVIEW1_REACTOR_ADAPTER,
-        )?
+    let mut linker = wit_component::Linker::default();
+    linker.encoder().validate(true);
+    linker.library(
+        "componentize_qjs_runtime.wasm",
+        runtime_wasm(opts.runtime),
+        false,
+    )?;
+    linker.library("wit-dylib.wasm", &wit_dylib, false)?;
+    linker.encoder().adapter(
+        "wasi_snapshot_preview1",
+        WASI_SNAPSHOT_PREVIEW1_REACTOR_ADAPTER,
+    )?;
+
+    let pre_wizer_component = linker
         .encode()
         .context("failed to link and encode component")?;
 
@@ -231,6 +233,7 @@ async fn wizer_init(
     let mut config = Config::new();
     config.wasm_component_model(true);
     config.wasm_component_model_async(true);
+    config.wasm_component_model_map(true);
 
     let engine = Engine::new(&config)?;
     let mut store = Store::new(&engine, Ctx { wasi, table });
 
@@ -5,11 +5,11 @@
 //! 2. Create a "stub world" where the WASI imports become exports
 //! 3. Use `dummy_module` to generate a core module with trap implementations
 //! 4. Encode it as a stub component
-//! 5. Use `wac-graph` to compose the stub into the original component
+//! 5. Use `wasm-compose` to compose the stub into the original component
 
 use anyhow::{Context, Result, bail};
 use indexmap::IndexMap;
-use wac_graph::{CompositionGraph, EncodeOptions, plug, types::Package};
+use wasm_compose::{composer::ComponentComposer, config::Config as ComposeConfig};
 use wit_component::{ComponentEncoder, StringEncoding, dummy_module, embed_component_metadata};
 use wit_parser::decoding::{DecodedWasm, decode};
 use wit_parser::{Docs, ManglingAndAbi, Resolve, Stability, World, WorldItem, WorldKey};
@@ -47,22 +47,22 @@ fn stub_imports(component: &[u8], should_stub: impl Fn(&str) -> bool) -> Result<
     let stub_component =
         make_stub_component(&resolve, world, &imports).context("failed to build stub component")?;
 
-    let mut graph = CompositionGraph::new();
+    let dir = tempfile::tempdir().context("failed to create composition directory")?;
+    let component_path = dir.path().join("original.wasm");
+    let stub_path = dir.path().join("stubs.wasm");
 
-    let orig_pkg = Package::from_bytes("original", None, component.to_vec(), graph.types_mut())
-        .context("failed to register original component")?;
+    std::fs::write(&component_path, component).context("failed to stage original component")?;
+    std::fs::write(&stub_path, stub_component).context("failed to stage stub component")?;
 
-    let stub_pkg = Package::from_bytes("stubs", None, stub_component, graph.types_mut())
-        .context("failed to register stub component")?;
-
-    let orig_id = graph.register_package(orig_pkg)?;
-    let stub_id = graph.register_package(stub_pkg)?;
-
-    plug(&mut graph, vec![stub_id], orig_id)?;
+    let config = ComposeConfig {
+        dir: dir.path().to_path_buf(),
+        definitions: vec!["stubs.wasm".into()],
+        ..Default::default()
+    };
 
-    graph
-        .encode(EncodeOptions::default())
-        .context("failed to encode composed component")
+    ComponentComposer::new(&component_path, &config)
+        .compose()
+        .context("failed to compose stub component")
 }
 
 /// Build a component that exports trap implementations for the given imports.
 
@@ -13,8 +13,8 @@ crate-type = ["cdylib"]
 
 [dependencies]
 rquickjs = { version = "0.12", default-features = false, features = ["bindgen", "disable-assertions", "loader", "std", "macro"] }
-wit-bindgen = "0.60"
-wit-dylib-ffi = { version = "0.1.0", git = "https://github.com/bytecodealliance/wasm-tools", default-features = false, features = ["async-raw"] }
+wit-bindgen = "0.61"
+wit-dylib-ffi = { version = "0.1.0", git = "https://github.com/bytecodealliance/wasm-tools", tag = "v1.258.0", default-features = false, features = ["async-raw"] }
 heck = "0.5"
 num_enum = { version = "0.7", default-features = false }
 smallvec = "1"
 
@@ -9,11 +9,12 @@ use crate::trivia::fn_lookup;
 use crate::{BorrowedResource, QjsCallContext, with_ctx};
 
 use rquickjs::class::Class;
-use rquickjs::{Coerced, IntoJs, Persistent, Symbol, Value};
+use rquickjs::function::This;
+use rquickjs::{Coerced, Constructor, Function, IntoJs, Persistent, Symbol, Value};
 use smallvec::SmallVec;
 use wit_dylib_ffi::{
-    Call, Enum, Flags, Future, List, Record, Resource, Stream, Tuple, Type, Variant, WitOption,
-    WitResult,
+    Call, Enum, Flags, Future, List, Map, Record, Resource, Stream, Tuple, Type, Variant,
+    WitOption, WitResult,
 };
 
 use std::alloc::Layout;
@@ -202,7 +203,7 @@ impl Call for QjsCallContext {
         })
     }
 
-    fn pop_iter_next(&mut self, _ty: List) {
+    fn pop_list_iter_next(&mut self, _ty: List) {
         let index = *self.iter_stack.last().expect("iter_stack underflow");
         let arr_persistent = self.stack.last().expect("stack underflow").clone();
 
@@ -216,11 +217,53 @@ impl Call for QjsCallContext {
         *self.iter_stack.last_mut().unwrap() = index + 1;
     }
 
-    fn pop_iter(&mut self, _ty: List) {
+    fn pop_list_iter(&mut self, _ty: List) {
         self.iter_stack.pop().expect("iter_stack underflow");
         self.stack.pop().expect("stack underflow");
     }
 
+    fn pop_map(&mut self, _ty: Map) -> usize {
+        let persistent = self.stack.pop().expect("stack underflow");
+
+        with_ctx(|ctx| {
+            let value = persistent.restore(ctx).unwrap();
+            let map = value.as_object().expect("expected Map");
+            let constructor: Constructor = ctx.globals().get("Map").expect("Map not found");
+            assert!(map.is_instance_of(&constructor), "expected Map");
+
+            let len = map.get("size").expect("expected Map size");
+            let entries: Function = map.get("entries").expect("Map.entries not found");
+            let iterator: Value = entries
+                .call((This(map.clone()),))
+                .expect("failed to create Map iterator");
+            self.stack.push(Persistent::save(ctx, iterator));
+            len
+        })
+    }
+
+    fn pop_map_iter_next(&mut self, _ty: Map) {
+        let persistent = self.stack.last().expect("stack underflow").clone();
+
+        with_ctx(|ctx| {
+            let value = persistent.restore(ctx).unwrap();
+            let iterator = value.as_object().expect("expected Map iterator");
+            let next: Function = iterator.get("next").expect("Map iterator.next not found");
+            let result: rquickjs::Object = next
+                .call((This(iterator.clone()),))
+                .expect("failed to advance Map iterator");
+            let entry: rquickjs::Array = result.get("value").expect("expected Map entry");
+            let key: Value = entry.get(0).expect("expected Map key");
+            let value: Value = entry.get(1).expect("expected Map value");
+
+            self.stack.push(Persistent::save(ctx, value));
+            self.stack.push(Persistent::save(ctx, key));
+        });
+    }
+
+    fn pop_map_iter(&mut self, _ty: Map) {
+        self.stack.pop().expect("stack underflow");
+    }
+
     fn pop_option(&mut self, ty: WitOption) -> u32 {
         let persistent = self.stack.pop().expect("stack underflow");
 
@@ -509,6 +552,31 @@ impl Call for QjsCallContext {
         });
     }
 
+    fn push_map(&mut self, _ty: Map, _capacity: usize) {
+        with_ctx(|ctx| {
+            let constructor: Constructor = ctx.globals().get("Map").expect("Map not found");
+            let map: Value = constructor.construct(()).expect("failed to create Map");
+            self.stack.push(Persistent::save(ctx, map));
+        });
+    }
+
+    fn map_append(&mut self, _ty: Map) {
+        let value = self.stack.pop().expect("stack underflow");
+        let key = self.stack.pop().expect("stack underflow");
+        let map_persistent = self.stack.last().expect("stack underflow").clone();
+
+        with_ctx(|ctx| {
+            let map_value = map_persistent.restore(ctx).unwrap();
+            let map = map_value.as_object().expect("expected Map");
+            let set: Function = map.get("set").expect("Map.set not found");
+            let key = key.restore(ctx).unwrap();
+            let value = value.restore(ctx).unwrap();
+            let _: Value = set
+                .call((This(map.clone()), key, value))
+                .expect("failed to append Map entry");
+        });
+    }
+
     fn push_option(&mut self, ty: WitOption, is_some: bool) {
         if option_is_nested(ty) {
             // Nested option: wrap so `none` and `some(none)` stay distinct.
 
@@ -140,6 +140,7 @@ stream<message>` adds `wit.Stream.PROMPT_STREAM`.
 | Results | `RESULT_STRING_U32` | `result<string, u32>` |
 | Tuples | `TUPLE_U32_STRING` | `tuple<u32, string>` |
 | Lists | `LIST_U8` | `list<u8>` |
+| Maps | `MAP_STRING_U32` | `map<string, u32>` |
 | Nested streams/futures | `STREAM_U8`, `FUTURE_STRING` | `stream<u8>`, `future<string>` |
 | Unit | `UNIT` | (no payload) |
 
@@ -268,6 +269,7 @@ represented directly by their values. Resources are exposed as classes.
 | Variants | `{ tag, val }` (string tag) | `{ tag: "case-a", val }` |
 | Flags | `{ name: boolean }` object | `{ flagA: true, flagB: false }` |
 | Records | object, camelCase fields | `{ fieldName: value }` |
+| Maps | `Map` | `new Map([["key", value]])` |
 | Resources | class instance; methods on prototype | `input.blockingRead(n)` |
 
 ### Export Functions