From 3a2f6ba2f9f270c637ac7b6bdff2f7f989b9fbaa Mon Sep 17 00:00:00 2001
From: Tobias Schlatter <schlatter.tobias@gmail.com>
Date: Wed, 4 Sep 2024 13:46:57 +0200
Subject: [PATCH] RFC: feat: support pattern properties

---
 .../src/transform/schema-object.ts            | 23 +++++++++++++++----
 packages/openapi-typescript/src/types.ts      |  1 +
 2 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/packages/openapi-typescript/src/transform/schema-object.ts b/packages/openapi-typescript/src/transform/schema-object.ts
index 7e74f094c..cb607a711 100644
--- a/packages/openapi-typescript/src/transform/schema-object.ts
+++ b/packages/openapi-typescript/src/transform/schema-object.ts
@@ -434,6 +434,9 @@ function transformSchemaObjectCore(schemaObject: SchemaObject, options: Transfor
 
   if (
     ("properties" in schemaObject && schemaObject.properties && Object.keys(schemaObject.properties).length) ||
+    ("patternProperties" in schemaObject &&
+      schemaObject.patternProperties &&
+      Object.keys(schemaObject.patternProperties).length) ||
     ("additionalProperties" in schemaObject && schemaObject.additionalProperties) ||
     ("$defs" in schemaObject && schemaObject.$defs)
   ) {
@@ -526,13 +529,23 @@ function transformSchemaObjectCore(schemaObject: SchemaObject, options: Transfor
       );
     }
 
-    // additionalProperties
-    if (schemaObject.additionalProperties || options.ctx.additionalProperties) {
+    // additionalProperties / patternProperties
+    if (schemaObject.additionalProperties || options.ctx.additionalProperties || schemaObject.patternProperties) {
+      const addlTypes = [];
+
       const hasExplicitAdditionalProperties =
         typeof schemaObject.additionalProperties === "object" && Object.keys(schemaObject.additionalProperties).length;
-      const addlType = hasExplicitAdditionalProperties
-        ? transformSchemaObject(schemaObject.additionalProperties as SchemaObject, options)
-        : UNKNOWN;
+
+      if (hasExplicitAdditionalProperties) {
+        addlTypes.push(transformSchemaObject(schemaObject.additionalProperties as SchemaObject, options));
+      }
+
+      for (const [_, v] of getEntries(schemaObject.patternProperties ?? {}, options.ctx)) {
+        addlTypes.push(transformSchemaObject(v, options));
+      }
+
+      const addlType = addlTypes ? tsUnion(addlTypes) : UNKNOWN;
+
       return tsIntersection([
         ...(coreObjectType.length ? [ts.factory.createTypeLiteralNode(coreObjectType)] : []),
         ts.factory.createTypeLiteralNode([
diff --git a/packages/openapi-typescript/src/types.ts b/packages/openapi-typescript/src/types.ts
index d045d521d..f143e3add 100644
--- a/packages/openapi-typescript/src/types.ts
+++ b/packages/openapi-typescript/src/types.ts
@@ -502,6 +502,7 @@ export interface ObjectSubtype {
   type: "object" | ["object", "null"];
   properties?: { [name: string]: SchemaObject | ReferenceObject };
   additionalProperties?: boolean | Record<string, never> | SchemaObject | ReferenceObject;
+  patternProperties?: Record<string, SchemaObject | ReferenceObject>;
   required?: string[];
   allOf?: (SchemaObject | ReferenceObject)[];
   anyOf?: (SchemaObject | ReferenceObject)[];