Fix record-based map keys for JS

3 files changed, 23 insertions, 1 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index bbf9e55..cb51916 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@
 
 ## Unreleased
 
+- Fixed a bug where record-based map keys would clash in JavaScript.
 - The `eunit` Erlang headers are no longer required to compile this package.
 - Fixed a bug where the `string.length` function would cause a JavaScript error
   for empty strings on older JavaScript runtimes.
diff --git a/src/gleam_stdlib.mjs b/src/gleam_stdlib.mjs
index a4afc1b..280cd95 100644
--- a/src/gleam_stdlib.mjs
+++ b/src/gleam_stdlib.mjs
@@ -279,7 +279,7 @@ class Map {
     if (existing) {
       return existing;
     } else if (value instanceof Object) {
-      let hashcode = JSON.stringify(value);
+      let hashcode = inspect(value);
       HASHCODE_CACHE.set(value, hashcode);
       return hashcode;
     } else {
diff --git a/test/gleam/map_test.gleam b/test/gleam/map_test.gleam
index 95ed66b..17db0ac 100644
--- a/test/gleam/map_test.gleam
+++ b/test/gleam/map_test.gleam
@@ -46,6 +46,12 @@ pub fn new_test() {
   |> should.equal([])
 }
 
+type Key {
+  A
+  B
+  C
+}
+
 pub fn get_test() {
   let proplist = [#(4, 0), #(1, 1)]
   let m = map.from_list(proplist)
@@ -61,6 +67,21 @@ pub fn get_test() {
   m
   |> map.get(2)
   |> should.equal(Error(Nil))
+
+  let proplist = [#(A, 0), #(B, 1)]
+  let m = map.from_list(proplist)
+
+  m
+  |> map.get(A)
+  |> should.equal(Ok(0))
+
+  m
+  |> map.get(B)
+  |> should.equal(Ok(1))
+
+  m
+  |> map.get(C)
+  |> should.equal(Error(Nil))
 }
 
 pub fn insert_test() {