fix decode_map throwing when `null` is being passed in (#432)

2 files changed, 15 insertions, 4 deletions

diff --git a/src/gleam_stdlib.erl b/src/gleam_stdlib.erl
index e1fdbb1..33c9609 100644
--- a/src/gleam_stdlib.erl
+++ b/src/gleam_stdlib.erl
@@ -41,6 +41,7 @@ decode_error_msg(Expected, Data) when is_binary(Expected) ->
 decode_error(Expected, Got) when is_binary(Expected) andalso is_binary(Got) ->
     {error, [{decode_error, Expected, Got, []}]}.
 
+classify_dynamic(nil) -> <<"Nil">>;
 classify_dynamic(X) when is_atom(X) -> <<"Atom">>;
 classify_dynamic(X) when is_binary(X) -> <<"String">>;
 classify_dynamic(X) when is_bitstring(X) -> <<"BitString">>;
diff --git a/src/gleam_stdlib.mjs b/src/gleam_stdlib.mjs
index 632c668..2b0a6e1 100644
--- a/src/gleam_stdlib.mjs
+++ b/src/gleam_stdlib.mjs
@@ -392,11 +392,11 @@ export function regex_scan(regex, string) {
     const submatches = [];
     for (let n = match.length - 1; n > 0; n--) {
       if (match[n]) {
-        submatches[n-1] = new Some(match[n])
-        continue
+        submatches[n - 1] = new Some(match[n]);
+        continue;
       }
-      if(submatches.length > 0) {
-        submatches[n-1] = new None()
+      if (submatches.length > 0) {
+        submatches[n - 1] = new None();
       }
     }
     return new RegexMatch(content, List.fromArray(submatches));
@@ -564,6 +564,10 @@ export function classify_dynamic(data) {
     return "Map";
   } else if (typeof data === "number") {
     return "Float";
+  } else if (data === null) {
+    return "Null";
+  } else if (data === undefined) {
+    return "Nil";
   } else {
     let type = typeof data;
     return type.charAt(0).toUpperCase() + type.slice(1);
@@ -633,6 +637,12 @@ export function decode_map(data) {
   if (data instanceof PMap) {
     return new Ok(PMap.fromMap(data));
   }
+  if (data == null) {
+    return decoder_error("Map", data);
+  }
+  if (typeof data !== "object") {
+    return decoder_error("Map", data);
+  }
   const proto = Object.getPrototypeOf(data);
   if (proto === Object.prototype || proto === null) {
     return new Ok(PMap.fromObject(data));