From a1dd6b94a852f0e74797c45ed03e0732a062cd96 Mon Sep 17 00:00:00 2001
From: Yuta Saito <kateinoigakukun@gmail.com>
Date: Sat, 15 Feb 2025 02:27:55 +0000
Subject: [PATCH] Suggest adding `gem "js"` to Gemfile when failing to
 instantiate Ruby VM

---
 packages/npm-packages/ruby-wasm-wasi/src/vm.ts | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/packages/npm-packages/ruby-wasm-wasi/src/vm.ts b/packages/npm-packages/ruby-wasm-wasi/src/vm.ts
index 01f9530e4c..ef4ba9802f 100644
--- a/packages/npm-packages/ruby-wasm-wasi/src/vm.ts
+++ b/packages/npm-packages/ruby-wasm-wasi/src/vm.ts
@@ -132,7 +132,12 @@ export class RubyVM {
     vm.addToImports(imports);
     options.addToImports?.(imports);
     const instance = await WebAssembly.instantiate(module, imports);
-    await vm.setInstance(instance);
+    try {
+      await vm.setInstance(instance);
+    } catch (e) {
+      console.error("Failed to instantiate Ruby VM. Please make sure that you have added `gem \"js\"` to your Gemfile.");
+      throw e;
+    }
     options.setMemory?.(instance.exports.memory as WebAssembly.Memory);
     wasip1.initialize(instance);
     vm.initialize(options.args);