A collection of ComfyUI utility nodes: a **dynamic JSON loader** that auto-creates outputs from any JSON file, **string/path helpers**, and a **preview-to-LoadImage bridge** that lets you push generated images (with optional masks) into LoadImage nodes. ## Features - **Auto-discovery** — reads JSON keys and exposes them as named outputs - **Type detection** — `INT`, `FLOAT`, `STRING` types with colored connectors - **Batch support** — `sequence_number` input for `batch_data` arrays - **Connection-safe refresh** — adding new keys preserves existing links - **Workflow persistence** — keys, types, and connections survive save/reload ## Installation ### ComfyUI Manager Search for **JSON Dynamic Loader** in the ComfyUI Manager registry. ### Manual ```bash cd ComfyUI/custom_nodes/ git clone https://github.com/ethanfel/ComfyUI-JSON-Dynamic.git # Restart ComfyUI ``` ## Usage 1. Add **JSON Dynamic Loader** node to your workflow 2. Enter a `json_path` and `sequence_number` 3. Click **Refresh Outputs** 4. Outputs appear named after your JSON keys with correct types 5. Connect to downstream nodes

Node diagram showing JSON Dynamic Loader connected to KSampler

## Type Handling | JSON type | Output type | Connector | |:---|:---|:---| | `42` (integer) | `INT` | Blue | | `3.14` (float) | `FLOAT` | Teal | | `"hello"` (string) | `STRING` | Pink | | `true` / `false` | `STRING` (`"true"` / `"false"`) | Pink | ## JSON Format ### Flat JSON (single segment) For simple use cases, the node reads keys directly from the root object. The `sequence_number` input is ignored. ```json { "general_prompt": "A cinematic scene...", "seed": 42, "flf": 0.5, "camera": "pan_left" } ``` ### Batch JSON (multiple segments) For multi-shot workflows, wrap entries in a `batch_data` array. Each entry is a **segment** representing one shot/scene with its own settings. The `sequence_number` input selects which segment to read. ```json { "batch_data": [ { "sequence_number": 1, "general_prompt": "Wide establishing shot of a city", "seed": 42, "camera": "static", "flf": 0.0 }, { "sequence_number": 2, "general_prompt": "Close-up of the protagonist", "seed": 108, "camera": "pan_left", "flf": 0.5, "my_custom_key": "only on this segment" }, { "sequence_number": 3, "general_prompt": "Aerial drone shot over rooftops", "seed": 77, "camera": "zoom_in", "flf": 0.8 } ] } ``` ### Segment lookup The node resolves which segment to read using this logic: 1. **Match by `sequence_number` field** — scans `batch_data` for an entry whose `sequence_number` matches the input 2. **Fallback to array index** — if no match is found, uses `sequence_number - 1` as the array index (clamped to bounds) 3. **No `batch_data`** — reads keys from the root object directly This means segments don't need to be in order and can have gaps (e.g. 1, 5, 10). Each segment can have different keys — click **Refresh Outputs** after changing `sequence_number` if the keys differ between segments.

Segment lookup diagram showing batch_data selection

## String & Path Utility Nodes Four additional nodes that replace common multi-node chains for string and path operations. ### Path Join (`utils/path`) Joins 1–6 path segments using `os.path.join` with automatic normalization. | Input | Type | Notes | |:---|:---|:---| | `segment_1` | STRING | Required | | `segment_2` – `segment_6` | STRING | Optional | **Output:** `path` (STRING) ### String Format (`utils/string`) Python format-string templating (`{0}/{1:04d}.{2}`) with up to 8 connected inputs. Handles zero-padding, type conversion, and arbitrary templates in one node. | Input | Type | Notes | |:---|:---|:---| | `template` | STRING | Format string, e.g. `{0}/{1:04d}` | | `v0` – `v7` | any | Optional values to substitute | **Output:** `string` (STRING) ### String Extract (`utils/string`) Extracts substrings with 3 modes: | Mode | Description | |:---|:---| | `split_take` | Split on delimiter, take part at index (negative indices supported) | | `between` | Extract text between two delimiters | | `filename_parts` | Decompose path into dirname / basename / extension | **Outputs:** `result`, `dirname`, `basename`, `extension` (all STRING) ### String Switch (`utils/string`) Boolean-based selection with built-in default values. | Input | Type | Notes | |:---|:---|:---| | `condition` | BOOLEAN | Required | | `on_true` / `on_false` | any | Optional connected values | | `default_true` / `default_false` | STRING | Fallback widget values | **Output:** `result` (any) When a connected input (`on_true`/`on_false`) is present it takes priority; otherwise the corresponding `default_*` string widget is used. ## Image Utility Nodes ### Preview to Load Image (`utils/image`) Previews an image like the built-in PreviewImage node, but also saves a copy to ComfyUI's `input/` folder so you can push it into any **LoadImage** node with one click. | Input | Type | Notes | |:---|:---|:---| | `images` | IMAGE | Required | | `filename` | STRING | Name for the saved file (without extension, default `preview`) | | `mask` | MASK | Optional — embedded as the PNG alpha channel | **Widgets (JS-side):** | Widget | Description | |:---|:---| | `load_image_node_id` | ID of the target LoadImage node | | **Send to Load Image** | Button — sets the target node's image selector to the saved file | **How it works:** 1. On execution, the node saves a temp preview (displayed in the node) and a permanent copy to `input/{filename}.png` 2. If a **mask** is connected, it is embedded as the PNG's alpha channel — LoadImage will automatically output it as its mask 3. Enter the target LoadImage node's ID and click **Send to Load Image** — the target's image dropdown updates immediately, no restart needed ## License [Apache 2.0](LICENSE)

Name	Type	Default	Description
condition	BOOLEAN	true	—
on_trueopt	*		—
on_falseopt	*		—
default_trueopt	STRING		—
default_falseopt	STRING		—

String Switch

Inputs (5)

Outputs (1)