From ed26b3197ef5e753a27d12f0c30d5f4bc6bd157e Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Sun, 11 Oct 2020 22:46:05 +0100
Subject: [PATCH] improve a message

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---
 wasm/wasm.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/wasm/wasm.rs b/wasm/wasm.rs
index af7a2c7e..8f431511 100644
--- a/wasm/wasm.rs
+++ b/wasm/wasm.rs
@@ -31,7 +31,8 @@ impl<E:Display, V> WasmResult<V> for Result<V, E> {
 #[wasm_bindgen]
 pub fn check(packed: &JsValue) {
   let s = packed.as_string().ok_or_else(
-    ||"packed Z coordinate wrong JS type (not a string)"
+    ||format!("packed Z coordinate wrong JS type (not a string): {:?}",
+              packed)
   ).e()?;
   ZCoord::check_str(&s).ok_or(zcoord::ParseError).e()?;
 }
-- 
2.30.2