pkg/dart2wasm/bin/run_wasm.js

// Copyright (c) 2022, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
//
// Runner V8 script for testing dart2wasm, takes ".wasm" files as arguments.
//
// Run as follows:
//
// $> d8 --experimental-wasm-gc --wasm-gc-js-interop --experimental-wasm-stack-switching --experimental-wasm-type-reflection run_wasm.js -- <dart_module>.wasm [<ffi_module>.wasm]
//
// If an FFI module is specified, it will be instantiated first, and its
// exports will be supplied as imports to the Dart module under the 'ffi'
// module name.

// We would like this itself to be a ES module rather than a script, but 
// unfortunately d8 does not return a failed error code if an unhandled
// exception occurs asynchronously in an ES module.
const main = async () => {
    const dart2wasm = await import('./dart2wasm_runtime.mjs');
    function compile(filename) {
        // Create a Wasm module from the binary wasm file.
        var bytes = readbuffer(filename);
        return new WebAssembly.Module(bytes);
    }

    function instantiate(filename, imports) {
        return new WebAssembly.Instance(compile(filename), imports);
    }

    let importObject = {};

    // Is an FFI module specified?
    if (arguments.length > 1) {
        // instantiate FFI module
        var ffiInstance = instantiate(arguments[1], {});
        // Make its exports available as imports under the 'ffi' module name
        importObject.ffi = ffiInstance.exports;
    }

    // Instantiate the Dart module, importing from the global scope.
    var dartInstance = await dart2wasm.instantiate(Promise.resolve(compile(arguments[0])), Promise.resolve(importObject));

    // Call `main`. If tasks are placed into the event loop (by scheduling tasks
    // explicitly or awaiting Futures), these will automatically keep the script
    // alive even after `main` returns.
    await dart2wasm.invoke(dartInstance);
};
main();