feat: Add support for unevaluatedProperties in JSON Schema

Add support for the unevaluatedProperties keyword from JSON Schema draft 2019-09/2020-12.
When additionalProperties is not defined, unevaluatedProperties is now used as a fallback
to determine the type of additional properties in an object.

This fixes issues where objects using unevaluatedProperties would generate incorrect
types (e.g., map[string]interface{} instead of properly typed maps in Go).

Author: haya14busa

packages/quicktype-core/src/input/JSONSchemaInput.ts

@@ -1108,6 +1108,11 @@ async function addTypesInSchema(
             ) {
                 additionalProperties = schema.patternProperties[".*"];
             }
+            
+            // Handle unevaluatedProperties if additionalProperties is not defined
+            if (additionalProperties === undefined && schema.unevaluatedProperties !== undefined) {
+                additionalProperties = schema.unevaluatedProperties;
+            }
 
             const objectAttributes = combineTypeAttributes(
                 "union",

test/inputs/schema/unevaluated-properties.1.json

@@ -0,0 +1,14 @@
+{
+    "config": {
+        "name": "test-config",
+        "settings": {
+            "option1": [
+                {"key": "foo", "value": "bar"},
+                {"key": "baz", "value": "qux"}
+            ],
+            "option2": [
+                {"key": "hello", "value": "world"}
+            ]
+        }
+    }
+}

test/inputs/schema/unevaluated-properties.2.json

@@ -0,0 +1,19 @@
+{
+    "config": {
+        "name": "multiple-versions",
+        "settings": {
+            "v1.0.0": [
+                {"key": "checksum1", "value": "abc123"},
+                {"key": "checksum2", "value": "def456"}
+            ],
+            "v1.1.0": [
+                {"key": "checksum1", "value": "ghi789"}
+            ],
+            "latest": [
+                {"key": "checksum1", "value": "jkl012"},
+                {"key": "checksum2", "value": "mno345"},
+                {"key": "checksum3", "value": "pqr678"}
+            ]
+        }
+    }
+}

test/inputs/schema/unevaluated-properties.schema

@@ -0,0 +1,46 @@
+{
+    "$schema": "https://json-schema.org/draft/2020-12/schema",
+    "$id": "unevaluated-properties.schema",
+    "title": "Test unevaluatedProperties support",
+    "type": "object",
+    "properties": {
+        "config": {
+            "$ref": "#/$defs/Config"
+        }
+    },
+    "$defs": {
+        "Config": {
+            "type": "object",
+            "properties": {
+                "name": {
+                    "type": "string"
+                },
+                "settings": {
+                    "$ref": "#/$defs/Settings"
+                }
+            }
+        },
+        "Settings": {
+            "type": "object",
+            "properties": {},
+            "unevaluatedProperties": {
+                "type": "array",
+                "items": {
+                    "$ref": "#/$defs/Item"
+                }
+            }
+        },
+        "Item": {
+            "type": "object",
+            "properties": {
+                "key": {
+                    "type": "string"
+                },
+                "value": {
+                    "type": "string"
+                }
+            },
+            "required": ["key", "value"]
+        }
+    }
+}