Merge pull request #113 from vim-denops/fix-request_async

🐛 Fix behavior of `request_async()`

denops/@denops-private/host/invoker.ts

@@ -40,10 +40,23 @@ export class Invoker {
     failure: string, // Callback ID
   ): Promise<void> {
     this.#service.dispatch(name, fn, args)
-      .then((r) => this.#service.call("denops#callback#call", success, r))
-      .catch((e) => this.#service.call("denops#callback#call", failure, e))
-      .catch((e) => {
-        console.error(`${e.stack ?? e.toString()}`);
+      .then(async (r) => {
+        try {
+          await this.#service.call("denops#callback#call", success, r);
+        } catch (e) {
+          console.error(`${e.stack ?? e.toString()}`);
+        }
+      })
+      .catch(async (e) => {
+        try {
+          await this.#service.call(
+            "denops#callback#call",
+            failure,
+            toErrorObject(e),
+          );
+        } catch (e) {
+          console.error(`${e.stack ?? e.toString()}`);
+        }
       });
     return Promise.resolve();
   }
@@ -52,3 +65,20 @@ export class Invoker {
 export function isInvokerMethod(value: string): value is keyof Invoker {
   return value in Invoker.prototype;
 }
+
+// https://github.com/vim-denops/denops.vim/issues/112
+function toErrorObject(
+  err: unknown,
+): { name: string; message: string; stack?: string } {
+  if (err instanceof Error) {
+    return {
+      name: err.name,
+      message: err.message,
+      stack: err.stack,
+    };
+  }
+  return {
+    name: typeof err,
+    message: `${err}`,
+  };
+}