zeromq · aminya · Jul 6, 2025 · Jul 6, 2025 · Jul 23, 2025 · Jul 23, 2025
diff --git a/.gitignore b/.gitignore
@@ -30,3 +30,6 @@ compile_commands.json
 /smoke-test-*
 /*.tgz
 /build-artifacts
+.parcel-cache/
+dist/
+*.wasm
diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -74,6 +74,42 @@ if(${ZMQ_ENABLE_SANITIZER_UNDEFINED})
   set(ENABLE_SANITIZER_UNDEFINED "ENABLE_SANITIZER_UNDEFINED")
 endif()
 
+option(ZMQ_WASM "Build for WebAssembly" OFF)
+set_option_from_env(ZMQ_WASM)
+
+if(ZMQ_WASM OR CMAKE_SYSTEM_NAME STREQUAL "Emscripten")
+  set(ZMQ_WASM TRUE)
+
+  # Compile for WebAssembly
+  set(VCPKG_HOST_TRIPLET wasm32-emscripten)
+  set(VCPKG_TARGET_TRIPLET wasm32-emscripten)
+
+  if ("$ENV{EMSCRIPTEN_ROOT}" STREQUAL "")
+    find_program(EMCC emcc REQUIRED)
+    get_filename_component(EMSCRIPTEN_ROOT "${EMCC}" DIRECTORY)
+  else()
+    set(EMSCRIPTEN_ROOT "$ENV{EMSCRIPTEN_ROOT}")
+  endif()
+
+  include(${EMSCRIPTEN_ROOT}/cmake/Modules/Platform/Emscripten.cmake)
+
+  set(CMAKE_LINKER "${EMSCRIPTEN_ROOT}/bin/lld${CMAKE_EXECUTABLE_SUFFIX}" CACHE STRING "Linker" FORCE)
+
+  add_compile_definitions("-D__wasm__" "-D__EMSCRIPTEN__")
+
+  # export an indirect function table for napi-wasm
+  add_link_options("--export-table")
+
+  # Add WebAssembly-specific exports for napi-wasm
+  add_link_options("SHELL:-s EXPORTED_FUNCTIONS=['_malloc','_free','_napi_register_wasm_v1']")
+  add_link_options("SHELL:-s EXPORTED_RUNTIME_METHODS=['ccall','cwrap']")
+  add_link_options("SHELL:-s ALLOW_MEMORY_GROWTH=1")
+  add_link_options("SHELL:-s ENVIRONMENT='node'")
+  add_link_options("SHELL:-s ERROR_ON_UNDEFINED_SYMBOLS=0")
+  add_link_options("SHELL:-s DISABLE_EXCEPTION_CATCHING=0")
+  add_link_options("--no-entry")
+endif()
+
 # Set MacOS deployment target
 if(APPLE)
   option(MACOSX_DEPLOYMENT_TARGET "MacOS deployment target" "10.15")
@@ -124,10 +160,17 @@ project_options(
   ENABLE_CACHE
   ENABLE_COMPILE_COMMANDS_SYMLINK
   ${ENABLE_SANITIZER_UNDEFINED}
+  ENABLE_INTERPROCEDURAL_OPTIMIZATION
 )
 
-file(GLOB_RECURSE SOURCES "./src/*.cc")
-add_library(addon SHARED ${SOURCES})
+file(GLOB_RECURSE SOURCES "./src/*.cc" "./src/*.cpp")
+
+if(ZMQ_WASM)
+  # For WebAssembly, create an executable instead of a shared library
+  add_executable(addon ${SOURCES})
+else()
+  add_library(addon SHARED ${SOURCES})
+endif()
 
 if(CMAKE_CXX_COMPILER_ID STREQUAL GNU
   OR CMAKE_CXX_COMPILER_ID STREQUAL Clang
@@ -145,6 +188,10 @@ if(ZMQ_NO_SYNC_RESOLVE)
   target_compile_definitions(addon PRIVATE ZMQ_NO_SYNC_RESOLVE)
 endif()
 
+if(ZMQ_WASM)
+  target_compile_definitions(addon PRIVATE ZMQ_WASM)
+endif()
+
 # ZeroMQ
 find_package(ZeroMQ CONFIG REQUIRED)
 target_link_system_libraries(addon PRIVATE libzmq libzmq-static)
@@ -168,7 +215,11 @@ if(WIN32)
 endif()
 
 # Use `.node` for the library without any "lib" prefix
-set_target_properties(addon PROPERTIES PREFIX "" SUFFIX ".node")
+if(ZMQ_WASM)
+  set_target_properties(addon PROPERTIES PREFIX "" SUFFIX ".wasm")
+else()
+  set_target_properties(addon PROPERTIES PREFIX "" SUFFIX ".node")
+endif()
 
 # Windows delay load node.exe
 if(WIN32)

diff --git a/examples/wasm/index.html b/examples/wasm/index.html
@@ -0,0 +1,7 @@
+<!DOCTYPE html>
+<html>
+  <title>ZeroMQ</title>
+  <body>
+    <script type="module" src="./index.mjs"></script>
+  </body>
+</html>
diff --git a/examples/wasm/index.mjs b/examples/wasm/index.mjs
@@ -0,0 +1,40 @@
+import {Environment, napi} from "napi-wasm"
+
+async function getWasm() {
+  if (typeof window === "undefined") {
+    // Nodejs
+    const fs = await import("fs/promises")
+    const path = await import("path")
+    const url = await import("url")
+
+    const __dirname = path.dirname(url.fileURLToPath(import.meta.url))
+
+    return (await fs.readFile(path.join(__dirname, "addon.wasm")))
+  }
+
+  // Browser
+  const response = await fetch("./addon.wasm")
+  if (!response.ok) {
+    throw new Error(`Failed to fetch wasm: ${response.statusText}`)
+  }
+  return await response.arrayBuffer()
+}
+
+async function main() {
+  const wasm = await getWasm()
+
+  const {instance} = await WebAssembly.instantiate(wasm, {
+    napi: napi,
+    env: {} // The env imports will be provided by napi-wasm
+  })
+
+  // Create an environment.
+  let env = new Environment(instance)
+  let exports = env.exports
+
+  console.log(exports)
+}
+
+main().catch(err => {
+  throw err
+})
diff --git a/examples/wasm/package.json b/examples/wasm/package.json
@@ -0,0 +1,15 @@
+{
+  "name": "browser",
+  "version": "1.0.0",
+  "description": "",
+  "scripts": {
+    "start": "parcel serve index.html"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC",
+  "packageManager": "[email protected]",
+  "devDependencies": {
+    "parcel": "^2.15.4"
+  }
+}