add create DICT and LIST from JSON string

CHANGELOG.md

@@ -5,6 +5,11 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+- Add "create DICT from JSON string" and "create LIST from JSON string" nodes to
+  parse a multiline JSON object/array into a DICT/LIST
+
 ## [1.8.1] - 2026-09-06
 
 - Add optional additional input for image saving to also save the prompt when provided

README.md

@@ -71,7 +71,7 @@ ComfyUI list manipulation nodes (for processing individual items):
 
 Dictionary manipulation nodes:
 
-- **Creation**: create (generic and type-specific), create from items, create from lists, fromkeys
+- **Creation**: create (generic and type-specific), create from JSON string, create from items, create from lists, fromkeys
 - **Access**: get, get_multiple, keys, values, items
 - **Modification**: set, update, setdefault, merge
 - **Removal**: pop, popitem, pop random, remove
@@ -102,7 +102,7 @@ Integer operation nodes:
 
 Python list manipulation nodes (as a single variable):
 
-- **Creation**: create LIST (generic and type-specific versions)
+- **Creation**: create LIST (generic and type-specific versions), create LIST from JSON string
 - **Modification**: append, extend, insert, remove, pop, pop random, set_item, shuffle
 - **Access**: get_item, first, last, slice, index, contains
 - **Information**: length, count

src/basic_data_handling/dict_nodes.py

@@ -4,6 +4,7 @@ from typing import (
 )
 
 from inspect import cleandoc
+import json
 import random
 
 try:
@@ -1067,12 +1068,49 @@ class DictValues(ComfyNodeABC):
         return (list(input_dict.values()),)
 
 
+class DictCreateFromJSONString(ComfyNodeABC):
+    """
+    Creates a DICT from a JSON object string.
+
+    This node takes a STRING that must contain a valid JSON object and
+    parses it into a DICT. The input must be a JSON object (enclosed in curly
+    braces); otherwise a clear error is raised.
+    """
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "json_string": (IO.STRING, {"default": "{}", "widgetType": "STRING", "tooltip": "STRING containing a JSON object to parse, e.g. {\"a\": 1}."}),
+            }
+        }
+
+    RETURN_TYPES = ("DICT",)
+    RETURN_NAMES = ("dict",)
+    OUTPUT_TOOLTIPS = ("The DICT parsed from the JSON object string.",)
+    CATEGORY = "Basic/DICT"
+    DESCRIPTION = cleandoc(__doc__ or "")
+    FUNCTION = "create_from_json"
+
+    def create_from_json(self, json_string: str) -> tuple[dict]:
+        try:
+            result = json.loads(json_string)
+        except json.JSONDecodeError as e:
+            raise ValueError(f"Invalid JSON in input string: {e}")
+        if not isinstance(result, dict):
+            raise ValueError(
+                "The JSON string must be a JSON object (enclosed in curly braces), "
+                f"not {type(result).__name__}."
+            )
+        return (result,)
+
+
 NODE_CLASS_MAPPINGS = {
     "Basic data handling: DictCreate": DictCreate,
     "Basic data handling: DictCreateFromBoolean": DictCreateFromBoolean,
     "Basic data handling: DictCreateFromFloat": DictCreateFromFloat,
     "Basic data handling: DictCreateFromInt": DictCreateFromInt,
     "Basic data handling: DictCreateFromString": DictCreateFromString,
+    "Basic data handling: DictCreateFromJSONString": DictCreateFromJSONString,
     "Basic data handling: DictCreateFromItemsDataList": DictCreateFromItemsDataList,
     "Basic data handling: DictCreateFromItemsList": DictCreateFromItemsList,
     "Basic data handling: DictCreateFromLists": DictCreateFromLists,
@@ -1105,6 +1143,7 @@ NODE_DISPLAY_NAME_MAPPINGS = {
     "Basic data handling: DictCreateFromFloat": "create DICT from FLOATs",
     "Basic data handling: DictCreateFromInt": "create DICT from INTs",
     "Basic data handling: DictCreateFromString": "create DICT from STRINGs",
+    "Basic data handling: DictCreateFromJSONString": "create DICT from JSON string",
     "Basic data handling: DictCreateFromItemsDataList": "create from items (data list)",
     "Basic data handling: DictCreateFromItemsList": "create from items (LIST)",
     "Basic data handling: DictCreateFromLists": "create from LISTs",

src/basic_data_handling/list_nodes.py

@@ -1,5 +1,6 @@
 from typing import Any
 from inspect import cleandoc
+import json
 
 try:
     from comfy.comfy_types.node_typing import IO, ComfyNodeABC
@@ -972,12 +973,49 @@ class ListToSet(ComfyNodeABC):
         return (set(list),)
 
 
+class ListCreateFromJSONString(ComfyNodeABC):
+    """
+    Creates a LIST from a JSON array string.
+
+    This node takes a STRING that must contain a valid JSON array and
+    parses it into a LIST. The input must be a JSON array (enclosed in square
+    brackets); otherwise a clear error is raised.
+    """
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "json_string": (IO.STRING, {"default": "[]", "widgetType": "STRING", "tooltip": "STRING containing a JSON array to parse, e.g. [1, 2, 3]."}),
+            }
+        }
+
+    RETURN_TYPES = ("LIST",)
+    RETURN_NAMES = ("list",)
+    OUTPUT_TOOLTIPS = ("The LIST parsed from the JSON array string.",)
+    CATEGORY = "Basic/LIST"
+    DESCRIPTION = cleandoc(__doc__ or "")
+    FUNCTION = "create_from_json"
+
+    def create_from_json(self, json_string: str) -> tuple[list[Any]]:
+        try:
+            result = json.loads(json_string)
+        except json.JSONDecodeError as e:
+            raise ValueError(f"Invalid JSON in input string: {e}")
+        if not isinstance(result, list):
+            raise ValueError(
+                "The JSON string must be a JSON array (enclosed in square brackets), "
+                f"not {type(result).__name__}."
+            )
+        return (result,)
+
+
 NODE_CLASS_MAPPINGS = {
     "Basic data handling: ListCreate": ListCreate,
     "Basic data handling: ListCreateFromBoolean": ListCreateFromBoolean,
     "Basic data handling: ListCreateFromFloat": ListCreateFromFloat,
     "Basic data handling: ListCreateFromInt": ListCreateFromInt,
     "Basic data handling: ListCreateFromString": ListCreateFromString,
+    "Basic data handling: ListCreateFromJSONString": ListCreateFromJSONString,
     "Basic data handling: ListAll": ListAll,
     "Basic data handling: ListAny": ListAny,
     "Basic data handling: ListAppend": ListAppend,
@@ -1013,6 +1051,7 @@ NODE_DISPLAY_NAME_MAPPINGS = {
     "Basic data handling: ListCreateFromFloat": "create LIST from FLOATs",
     "Basic data handling: ListCreateFromInt": "create LIST from INTs",
     "Basic data handling: ListCreateFromString": "create LIST from STRINGs",
+    "Basic data handling: ListCreateFromJSONString": "create LIST from JSON string",
     "Basic data handling: ListAll": "all",
     "Basic data handling: ListAny": "any",
     "Basic data handling: ListAppend": "append",

tests/test_dict_nodes.py

@@ -11,6 +11,7 @@ from src.basic_data_handling.dict_nodes import (
     DictCreateFromItemsList,
     DictCreateFromLists,
     DictCreateFromString,
+    DictCreateFromJSONString,
     DictExcludeKeys,
     DictFilterByKeys,
     DictFromKeys,
@@ -112,6 +113,20 @@ def test_dict_create_from_string():
     assert node.create() == ({},)
 
 
+def test_dict_create_from_json_string():
+    node = DictCreateFromJSONString()
+    # Single-line JSON object
+    assert node.create_from_json('{\n  "key1": "value1",\n  "key2": 2\n}') == ({"key1": "value1", "key2": 2},)
+    # Empty object
+    assert node.create_from_json("{}") == ({},)
+    # JSON array is not a valid object -> error
+    with pytest.raises(ValueError, match="JSON object"):
+        node.create_from_json("[1, 2, 3]")
+    # Malformed JSON -> error
+    with pytest.raises(ValueError):
+        node.create_from_json("{not json}")
+
+
 def test_dict_create_from_items_datalist():
     node = DictCreateFromItemsDataList()
     assert node.create_from_items(item=[("key1", "value1"), ("key2", "value2")]) == (_dict_x2,)

tests/test_list_nodes.py

@@ -10,6 +10,7 @@ from src.basic_data_handling.list_nodes import (
     ListCreateFromFloat,
     ListCreateFromInt,
     ListCreateFromString,
+    ListCreateFromJSONString,
     ListEnumerate,
     ListExtend,
     ListFirst,
@@ -257,6 +258,22 @@ def test_list_create_from_string():
     assert node.create_list() == ([],)
 
 
+def test_list_create_from_json_string():
+    node = ListCreateFromJSONString()
+    # Multiline JSON array
+    assert node.create_from_json('[\n  1,\n  2,\n  3\n]') == ([1, 2, 3],)
+    # Empty array
+    assert node.create_from_json("[]") == ([],)
+    # Mix of JSON types
+    assert node.create_from_json('["a", 1, true, null]') == (["a", 1, True, None],)
+    # JSON object is not a valid array -> error
+    with pytest.raises(ValueError, match="JSON array"):
+        node.create_from_json('{"a": 1}')
+    # Malformed JSON -> error
+    with pytest.raises(ValueError):
+        node.create_from_json("[1, 2,")
+
+
 def test_list_to_data_list():
     node = ListToDataList()
     input_list = [1, 2, 3]