From a8628c247394777a48faa4e6f63502bb184d8fb1 Mon Sep 17 00:00:00 2001
From: Phil Pluckthun <phil@kitten.sh>
Date: Sat, 3 Feb 2024 10:01:47 +0000
Subject: [PATCH] Make getVariables tail recursive

More correct, as per tail recursion in other
places, but `variables.ts` didn't get much
attention before
---
 src/variables.ts | 49 ++++++++++++++++++++++++++----------------------
 1 file changed, 27 insertions(+), 22 deletions(-)

diff --git a/src/variables.ts b/src/variables.ts
index da06d7b6..86e0c82a 100644
--- a/src/variables.ts
+++ b/src/variables.ts
@@ -67,27 +67,32 @@ type unwrapTypeRef<Type, Introspection extends IntrospectionLikeType> = Type ext
   ? _unwrapTypeRefRec<Type['type'], Introspection>
   : null | _unwrapTypeRefRec<Type, Introspection>;
 
-type getVariablesRec<Variables, Introspection extends IntrospectionLikeType> = Variables extends [
-  infer Variable,
-  ...infer Rest,
-]
-  ? (Variable extends { kind: Kind.VARIABLE_DEFINITION; variable: any; type: any }
-      ? Variable extends { defaultValue: undefined; type: { kind: Kind.NON_NULL_TYPE } }
-        ? {
-            [Name in Variable['variable']['name']['value']]: unwrapTypeRef<
-              Variable['type'],
-              Introspection
-            >;
-          }
-        : {
-            [Name in Variable['variable']['name']['value']]?: unwrapTypeRef<
-              Variable['type'],
-              Introspection
-            >;
-          }
-      : {}) &
-      getVariablesRec<Rest, Introspection>
-  : {};
+type _getVariablesRec<
+  Variables,
+  Introspection extends IntrospectionLikeType,
+  VariablesObject = {},
+> = Variables extends [infer Variable, ...infer Rest]
+  ? _getVariablesRec<
+      Rest,
+      Introspection,
+      (Variable extends { kind: Kind.VARIABLE_DEFINITION; variable: any; type: any }
+        ? Variable extends { defaultValue: undefined; type: { kind: Kind.NON_NULL_TYPE } }
+          ? {
+              [Name in Variable['variable']['name']['value']]: unwrapTypeRef<
+                Variable['type'],
+                Introspection
+              >;
+            }
+          : {
+              [Name in Variable['variable']['name']['value']]?: unwrapTypeRef<
+                Variable['type'],
+                Introspection
+              >;
+            }
+        : {}) &
+        VariablesObject
+    >
+  : VariablesObject;
 
 type getVariablesType<
   Document extends DocumentNodeLike,
@@ -96,7 +101,7 @@ type getVariablesType<
   kind: Kind.OPERATION_DEFINITION;
   variableDefinitions: any;
 }
-  ? obj<getVariablesRec<Document['definitions'][0]['variableDefinitions'], Introspection>>
+  ? obj<_getVariablesRec<Document['definitions'][0]['variableDefinitions'], Introspection>>
   : {};
 
 export type { getVariablesType };