Improve error messages

1 files changed, 11 insertions, 8 deletions

diff --git a/src/gleam_stdlib.js b/src/gleam_stdlib.js
index 7ecbe11..b743c03 100644
--- a/src/gleam_stdlib.js
+++ b/src/gleam_stdlib.js
@@ -518,24 +518,27 @@ export function decode_bit_string(data) {
     : decoder_error("BitString", data);
 }
 
+function decode_tuple_error(size, data) {
+  return decoder_error(
+    `Tuple of at least ${size} element${size == 1 ? "" : "s"}`,
+    data
+  );
+}
+
 export function decode_element(data, index) {
-  let error = (size) =>
-    decoder_error(
-      `Tuple of at least ${size} element${size == 1 ? "" : "s"}`,
-      data
-    );
-  if (!Array.isArray(data)) return error(index < 0 ? 1 : index + 1);
+  if (!Array.isArray(data))
+    return decode_tuple_error(index < 0 ? Math.abs(index) : index + 1, data);
   if (index >= 0) {
     if (index < data.length) {
       return new Ok(data[index]);
     } else {
-      return error(index + 1);
+      return decode_tuple_error(index + 1, data);
     }
   } else {
     if (Math.abs(index) <= data.length) {
       return new Ok(data[data.length + index]);
     } else {
-      return error(Math.abs(index));
+      return decode_tuple_error(Math.abs(index), data);
     }
   }
 }