Fix invalid TS definition for long variant constructors with no args

Author: richard-viney

CHANGELOG.md

@@ -70,3 +70,7 @@
 - Fixed a bug where the "pattern match on variable" code action would generate
   invalid patterns by repeating a variable name already used in the same pattern.
   ([Giacomo Cavalieri](https://github.com/giacomocavalieri))
+
+- Fix invalid TypeScript definition being generated for variant constructors
+  with long names that take no arguments.
+  ([Richard Viney](https://github.com/richard-viney))

compiler-core/src/javascript/tests/custom_types.rs

@@ -217,6 +217,17 @@ pub const local = TypeWithALongNameAndSeveralArguments("one", "two", "three", "f
     );
 }
 
+#[test]
+fn long_name_variant_without_arguments() {
+    assert_ts_def!(
+        r#"
+pub type TypeWithALongNameAndNoArguments{
+  TypeWithALongNameAndNoArguments
+}
+"#
+    );
+}
+
 #[test]
 fn custom_type_with_named_fields() {
     assert_js!(

compiler-core/src/javascript/tests/snapshots/gleam_core__javascript__tests__custom_types__long_name_variant_without_arguments.snap

@@ -0,0 +1,22 @@
+---
+source: compiler-core/src/javascript/tests/custom_types.rs
+expression: "\npub type TypeWithALongNameAndNoArguments{\n  TypeWithALongNameAndNoArguments\n}\n"
+snapshot_kind: text
+---
+----- SOURCE CODE
+
+pub type TypeWithALongNameAndNoArguments{
+  TypeWithALongNameAndNoArguments
+}
+
+
+----- TYPESCRIPT DEFINITIONS
+import type * as _ from "../gleam.d.mts";
+
+export class TypeWithALongNameAndNoArguments extends _.CustomType {}
+export function TypeWithALongNameAndNoArguments$TypeWithALongNameAndNoArguments(): TypeWithALongNameAndNoArguments$;
+export function TypeWithALongNameAndNoArguments$isTypeWithALongNameAndNoArguments(
+  value: TypeWithALongNameAndNoArguments$,
+): boolean;
+
+export type TypeWithALongNameAndNoArguments$ = TypeWithALongNameAndNoArguments;

compiler-core/src/javascript/typescript.rs

@@ -655,13 +655,21 @@ impl<'a> TypeScriptGenerator<'a> {
         )
         .to_doc();
 
+        let arguments = if arguments.is_empty() {
+            docvec!["(): "]
+        } else {
+            docvec![
+                "(",
+                docvec![break_("", ""), join(arguments, break_(",", ", ")),].nest(INDENT),
+                break_(",", ""),
+                "): ",
+            ]
+        };
+
         docvec![
             "export function ",
             name_with_generics(function_name, type_parameters),
-            "(",
-            docvec![break_("", ""), join(arguments, break_(",", ", ")),].nest(INDENT),
-            break_(",", ""),
-            "): ",
+            arguments,
             type_name_with_generics.clone(),
             ";"
         ]