Add JSONLoaderDynamic node with JS frontend for auto-discovered outputs

Dynamic node reads JSON keys and exposes them as outputs automatically
via 32 AnyType slots managed by a JS extension (show/hide/rename).
Includes /json_manager/get_keys API route, bool-safe type handling,
and workflow save/reload support.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

json_loader.py

@@ -6,6 +6,22 @@ from typing import Any
 logger = logging.getLogger(__name__)
 
 KEY_BATCH_DATA = "batch_data"
+MAX_DYNAMIC_OUTPUTS = 32
+
+
+class AnyType(str):
+    """Universal connector type that matches any ComfyUI type."""
+    def __ne__(self, __value: object) -> bool:
+        return False
+
+any_type = AnyType("*")
+
+
+try:
+    from server import PromptServer
+    from aiohttp import web
+except ImportError:
+    PromptServer = None
 
 
 def to_float(val: Any) -> float:
@@ -49,6 +65,69 @@ def read_json_data(json_path: str) -> dict[str, Any]:
         return {}
     return data
 
+# --- API Route ---
+if PromptServer is not None:
+    @PromptServer.instance.routes.get("/json_manager/get_keys")
+    async def get_keys_route(request):
+        json_path = request.query.get("path", "")
+        try:
+            seq = int(request.query.get("sequence_number", "1"))
+        except (ValueError, TypeError):
+            seq = 1
+        data = read_json_data(json_path)
+        target = get_batch_item(data, seq)
+        keys = list(target.keys()) if isinstance(target, dict) else []
+        return web.json_response({"keys": keys})
+
+
+# ==========================================
+# 0. DYNAMIC NODE
+# ==========================================
+
+class JSONLoaderDynamic:
+    @classmethod
+    def INPUT_TYPES(s):
+        return {
+            "required": {
+                "json_path": ("STRING", {"default": "", "multiline": False}),
+                "sequence_number": ("INT", {"default": 1, "min": 1, "max": 9999}),
+            },
+            "optional": {
+                "output_keys": ("STRING", {"default": ""}),
+            },
+        }
+
+    RETURN_TYPES = tuple(any_type for _ in range(MAX_DYNAMIC_OUTPUTS))
+    RETURN_NAMES = tuple(f"output_{i}" for i in range(MAX_DYNAMIC_OUTPUTS))
+    FUNCTION = "load_dynamic"
+    CATEGORY = "utils/json"
+    OUTPUT_NODE = False
+
+    def load_dynamic(self, json_path, sequence_number, output_keys=""):
+        data = read_json_data(json_path)
+        target = get_batch_item(data, sequence_number)
+
+        keys = [k.strip() for k in output_keys.split(",") if k.strip()] if output_keys else []
+
+        results = []
+        for key in keys:
+            val = target.get(key, "")
+            if isinstance(val, bool):
+                results.append(str(val).lower())
+            elif isinstance(val, int):
+                results.append(val)
+            elif isinstance(val, float):
+                results.append(val)
+            else:
+                results.append(str(val))
+
+        # Pad to MAX_DYNAMIC_OUTPUTS
+        while len(results) < MAX_DYNAMIC_OUTPUTS:
+            results.append("")
+
+        return tuple(results)
+
+
 # ==========================================
 # 1. STANDARD NODES (Single File)
 # ==========================================
@@ -270,6 +349,7 @@ class JSONLoaderCustom6:
 
 # --- Mappings ---
 NODE_CLASS_MAPPINGS = {
+    "JSONLoaderDynamic": JSONLoaderDynamic,
     "JSONLoaderLoRA": JSONLoaderLoRA,
     "JSONLoaderStandard": JSONLoaderStandard,
     "JSONLoaderVACE": JSONLoaderVACE,
@@ -282,6 +362,7 @@ NODE_CLASS_MAPPINGS = {
 }
 
 NODE_DISPLAY_NAME_MAPPINGS = {
+    "JSONLoaderDynamic": "JSON Loader (Dynamic)",
     "JSONLoaderLoRA": "JSON Loader (LoRAs Only)",
     "JSONLoaderStandard": "JSON Loader (Standard/I2V)",
     "JSONLoaderVACE": "JSON Loader (VACE Full)",