Provides utilities for loading and running WASM modules

Built on top of the Wasmer runtime.


Start by installing the tools needed to build the Wasmer runtime:

Basic Usage

As a simple example, we'll try to call a simple C function from Dart using
package:wasm. For a more detailed example that uses WASI, check out the
example directory.

  1. First create new Dart app folder: dart create wasmtest

  2. Add a dependency to package wasm in pubspec.yaml and run dart pub get

  3. Next run dart run wasm:setup to build the Wasmer runtime. This will take a few minutes.

  4. Then add a new file square.cc with the following contents:

    extern "C" int square(int n) { return n * n; }
  5. We can compile this C++ code to WASM using a recent version of the
    clang compiler:

    clang --target=wasm32 -nostdlib "-Wl,--export-all" "-Wl,--no-entry" -o square.wasm square.cc
  6. Replace the contents of your Dart program (bin/wasmtest.dart) with:

    import 'dart:io';
    import 'package:wasm/wasm.dart';
    void main() {
      final data = File('square.wasm').readAsBytesSync();
      final mod = WasmModule(data);
      final inst = mod.builder().build();
      final square = inst.lookupFunction('square');
  7. Run the Dart program: dart run. This should print:

    export memory: memory
    export function: int32 square(int32)