wasm: enable JSPI

Author: guybedford

src/node.cc

@@ -782,6 +782,9 @@ static ExitCode ProcessGlobalArgsInternal(std::vector<std::string>* args,
 
   v8_args.emplace_back("--js-source-phase-imports");
 
+  // WebAssembly JS Promise Integration
+  v8_args.emplace_back("--experimental-wasm-jspi");
+
 #ifdef __POSIX__
   // Block SIGPROF signals when sleeping in epoll_wait/kevent/etc.  Avoids the
   // performance penalty of frequent EINTR wakeups when the profiler is running.

test/fixtures/wasm/jspi.wasm

@@ -0,0 +1,20 @@
+import '../common/index.mjs';
+import { strictEqual } from 'node:assert';
+import { readSync } from '../common/fixtures.mjs';
+
+// Test Wasm JSPI
+{
+  const asyncImport = async (x) => {
+    await new Promise((resolve) => setTimeout(resolve, 10));
+    return x + 42;
+  };
+
+  const { instance } = await WebAssembly.instantiate(readSync('wasm/jspi.wasm'), {
+    js: {
+      async: new WebAssembly.Suspending(asyncImport),
+    },
+  });
+
+  const promisingExport = WebAssembly.promising(instance.exports.test);
+  strictEqual(await promisingExport(10), 52);
+}