diff --git a/Dockerfile b/Dockerfile
index d7e9092..beed103 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -2,7 +2,7 @@ FROM node:22-alpine@sha256:ed9736a13b88ba55cbc08c75c9edac8ae7f72840482e40324670b
 ARG UID=1000
 ARG GID=1000
 
-RUN apk add -U clang lld wasi-sdk && mkdir /home/node/llhttp
+RUN apk add -U clang lld wasi-sdk bash && mkdir /home/node/llhttp
 
 WORKDIR /home/node/llhttp
 
diff --git a/bin/build_wasm.sh b/bin/build_wasm.sh
new file mode 100755
index 0000000..a7d84af
--- /dev/null
+++ b/bin/build_wasm.sh
@@ -0,0 +1,67 @@
+#!/usr/bin/env bash
+
+set -e
+
+WASM_SRC="$(dirname "$0")/../"
+WASM_OUT="$(dirname "$0")/../build/wasm"
+
+cd "$WASM_SRC"
+
+if [[ -z "$WASM_PLATFORM" && -n "$1" ]]; then
+    WASM_PLATFORM=$(docker info -f "{{.OSType}}/{{.Architecture}}")
+fi
+
+case "$1" in
+    --prebuild)
+        exec docker build --platform="$WASM_PLATFORM" -t llhttp_wasm_builder . --load
+        ;;
+    --setup)
+        mkdir -p build
+        exit 0
+        ;;
+    --docker)
+        cmd=(docker run --rm --platform="$WASM_PLATFORM")
+        if [[ -z "$CI" ]]; then
+            cmd+=(-it)
+        fi
+        # Try to avoid root permission problems on compiled assets
+        # when running on linux.
+        # It will work flawessly if uid === gid === 1000
+        # there will be some warnings otherwise.
+        if [[ "$(uname)" == Linux ]]; then
+            cmd+=(--user "$(id -u):$(id -g)")
+        fi
+        cmd+=(--mount "type=bind,source=./build,target=/home/node/llhttp/build" llhttp_wasm_builder npm run wasm)
+
+        echo "> ${cmd[*]}"
+        exec "${cmd[@]}"
+        ;;
+esac
+
+mkdir -p "$WASM_OUT"
+
+npm run build
+
+clang \
+    --sysroot=/usr/share/wasi-sysroot \
+    -target wasm32-unknown-wasi \
+    -Ofast \
+    -fno-exceptions \
+    -fvisibility=hidden \
+    -mexec-model=reactor \
+    -Wl,-error-limit=0 \
+    -Wl,-O3 \
+    -Wl,--lto-O3 \
+    -Wl,--strip-all \
+    -Wl,--allow-undefined \
+    -Wl,--export-dynamic \
+    -Wl,--export-table \
+    -Wl,--export=malloc \
+    -Wl,--export=free \
+    -Wl,--no-entry \
+    build/c/*.c \
+    src/native/*.c \
+    -Ibuild \
+    -o "$WASM_OUT/llhttp.wasm"
+
+cp lib/llhttp/{constants,utils}.* "$WASM_OUT/"
diff --git a/bin/build_wasm.ts b/bin/build_wasm.ts
deleted file mode 100644
index 2d97a89..0000000
--- a/bin/build_wasm.ts
+++ /dev/null
@@ -1,101 +0,0 @@
-import { execSync } from 'child_process';
-import { copyFileSync, mkdirSync } from 'fs';
-import { join, resolve } from 'path';
-
-let platform = process.env.WASM_PLATFORM ?? '';
-const IS_CI = 'CI' in process.env;
-const WASM_OUT = resolve(__dirname, '../build/wasm');
-const WASM_SRC = resolve(__dirname, '../');
-
-if (!platform && process.argv[2]) {
-  platform = execSync('docker info -f "{{.OSType}}/{{.Architecture}}"').toString().trim();
-}
-
-if (process.argv[2] === '--prebuild') {
-  const cmd = `docker build --platform=${platform.toString().trim()} -t llhttp_wasm_builder . --load`;
-
-  console.log(`> ${cmd}\n\n`);
-  execSync(cmd, { stdio: 'inherit' });
-
-  process.exit(0);
-}
-
-if (process.argv[2] === '--setup') {
-  try {
-    mkdirSync(join(WASM_SRC, 'build'));
-    process.exit(0);
-  } catch (error: unknown) {
-    if (isErrorWithCode(error) && error.code !== 'EEXIST') {
-      throw error;
-    }
-    process.exit(0);
-  }
-}
-
-if (process.argv[2] === '--docker') {
-  let cmd = `docker run --rm --platform=${platform.toString().trim()}`;
-  if (!IS_CI) {
-    cmd += ' -it';
-  }
-  // Try to avoid root permission problems on compiled assets
-  // when running on linux.
-  // It will work flawessly if uid === gid === 1000
-  // there will be some warnings otherwise.
-  if (process.platform === 'linux') {
-    cmd += ` --user ${process.getuid!()}:${process.getegid!()}`;
-  }
-  cmd += ` --mount type=bind,source=${WASM_SRC}/build,target=/home/node/llhttp/build llhttp_wasm_builder npm run wasm`;
-
-  console.log(`> ${cmd}\n\n`);
-  execSync(cmd, { cwd: WASM_SRC, stdio: 'inherit' });
-  process.exit(0);
-}
-
-try {
-  mkdirSync(WASM_OUT);
-} catch (error: unknown) {
-  if (isErrorWithCode(error) && error.code !== 'EEXIST') {
-    throw error;
-  }
-}
-
-// Build ts
-execSync('npm run build', { cwd: WASM_SRC, stdio: 'inherit' });
-
-// Build wasm binary
-execSync(
-  `clang \
- --sysroot=/usr/share/wasi-sysroot \
- -target wasm32-unknown-wasi \
- -Ofast \
- -fno-exceptions \
- -fvisibility=hidden \
- -mexec-model=reactor \
- -Wl,-error-limit=0 \
- -Wl,-O3 \
- -Wl,--lto-O3 \
- -Wl,--strip-all \
- -Wl,--allow-undefined \
- -Wl,--export-dynamic \
- -Wl,--export-table \
- -Wl,--export=malloc \
- -Wl,--export=free \
- -Wl,--no-entry \
- ${join(WASM_SRC, 'build', 'c')}/*.c \
- ${join(WASM_SRC, 'src', 'native')}/*.c \
- -I${join(WASM_SRC, 'build')} \
- -o ${join(WASM_OUT, 'llhttp.wasm')}`,
-  { stdio: 'inherit' },
-);
-
-// Copy constants for `.js` and `.ts` users.
-copyFileSync(join(WASM_SRC, 'lib', 'llhttp', 'constants.js'), join(WASM_OUT, 'constants.js'));
-copyFileSync(join(WASM_SRC, 'lib', 'llhttp', 'constants.js.map'), join(WASM_OUT, 'constants.js.map'));
-copyFileSync(join(WASM_SRC, 'lib', 'llhttp', 'constants.d.ts'), join(WASM_OUT, 'constants.d.ts'));
-copyFileSync(join(WASM_SRC, 'lib', 'llhttp', 'utils.js'), join(WASM_OUT, 'utils.js'));
-copyFileSync(join(WASM_SRC, 'lib', 'llhttp', 'utils.js.map'), join(WASM_OUT, 'utils.js.map'));
-copyFileSync(join(WASM_SRC, 'lib', 'llhttp', 'utils.d.ts'), join(WASM_OUT, 'utils.d.ts'));
-
-function isErrorWithCode(error: unknown): error is Error & { code: string } {
-  return typeof error === 'object' && error !== null && 'code' in error;
-}
diff --git a/package.json b/package.json
index e7909c3..3d5fe83 100644
--- a/package.json
+++ b/package.json
@@ -14,7 +14,7 @@
     "build-ts": "tsc",
     "prebuild-wasm": "npm run wasm -- --prebuild && npm run wasm -- --setup",
     "build-wasm": "npm run wasm -- --docker",
-    "wasm": "ts-node bin/build_wasm.ts",
+    "wasm": "bash bin/build_wasm.sh",
     "clean": "rm -rf lib && rm -rf test/tmp",
     "prepare": "npm run clean && npm run build-ts",
     "test": "node -r ts-node/register/type-check ./test/md-test.ts",