👍 Add friendlyCall to helper module

Author: lambdalisue

denops_std/helper/README.md

@@ -26,6 +26,30 @@ export async function main(denops: Denops): Promise<void> {
 }
 ```
 
+### friendlyCall
+
+Use `friendlyCall()` to call given function and print a friendly error message
+(without stack trace) on failure. It's mainly designed for `dispatcher`
+functions.
+
+Note that it prints a stack trace when denops is running in debug mode.
+
+```typescript
+import { Denops } from "https://deno.land/x/denops_std/mod.ts";
+import { friendlyCall } from "https://deno.land/x/denops_std/helper/mod.ts";
+
+export async function main(denops: Denops): Promise<void> {
+  denops.dispatcher = {
+    "say": () => {
+      return friendlyCall(denops, async () => {
+        // Do whatever you want.
+        throw new Error("Some error occured");
+      });
+    },
+  };
+}
+```
+
 ### input
 
 Use `input()` which is a wrapper function of `input()` in

denops_std/helper/echo.ts

@@ -38,6 +38,30 @@ export async function echoerr(denops: Denops, message: string): Promise<void> {
   });
 }
 
+/**
+ * Call given function and print a friendly error message (without stack trace) on failure.
+ *
+ * Print a stack trace when denops is running in debug mode.
+ */
+export async function friendlyCall(
+  denops: Denops,
+  fn: () => Promise<unknown>,
+): Promise<unknown> {
+  if (denops.meta.mode === "debug") {
+    return await fn();
+  }
+  try {
+    return await fn();
+  } catch (e: unknown) {
+    if (e instanceof Error) {
+      const err: Error = e;
+      await echoerr(denops, `[${denops.name}]: ${err.message}`);
+    } else {
+      throw e;
+    }
+  }
+}
+
 async function echoVim(denops: Denops, message: string): Promise<void> {
   await load(denops, new URL("./echo.vim", import.meta.url));
   const waiter = deferred<void>();