JSON: Set Value¶
Sets a value inside JSON data using a dot-separated key path. It supports nested objects and arrays, auto-creating intermediate dictionaries and extending arrays as needed. Accepts either JSON objects/lists or JSON strings and returns the updated JSON data.
Usage¶
Use this node when you need to programmatically add or update fields in a JSON structure before passing it to subsequent steps (e.g., building request bodies, shaping configuration, or enriching data). Provide the JSON input, a dot-separated path (keys for objects and numeric indices for arrays), and the value to set.
Inputs¶
| Field | Required | Type | Description | Example |
|---|---|---|---|---|
| json_data | True | WILDCARD | The JSON data to modify. Can be a dict/list object or a JSON-formatted string. | {"user": {"name": "Ann"}} |
| key_path | True | STRING | Dot-separated path indicating where to set the value. Use object keys for maps and numeric indices for arrays. | user.profile.age or items.0.title |
| value | True | WILDCARD | The value to set at the specified path. Can be any JSON-serializable type. | 42 |
Outputs¶
| Field | Type | Description | Example |
|---|---|---|---|
| updated_data | WILDCARD | The JSON data after setting the specified value at the given path. If input was a JSON string, the output is a parsed JSON object/list. | {"user": {"profile": {"age": 42}}} |
Important Notes¶
- Key path format: Use dot notation for nested keys. Use numeric segments to index lists (e.g., "items.2.name").
- Auto-creation: Missing intermediate objects are created as empty dictionaries. When navigating lists, they are extended with empty objects during traversal and with nulls to reach the final index.
- String input handling: If json_data is a string, it is parsed before modification. Invalid JSON will result in returning the original data on error.
- Empty key_path behavior: If key_path is empty, the node returns the provided value directly as output.
- Invalid list index segments: Non-integer segments for list navigation or final index cause the node to return the original json_data unchanged.
- Type constraints: If the path navigates through a value that is neither a dict nor a list, the operation is aborted and the original json_data is returned.
Troubleshooting¶
- Value not updated: Verify key_path uses correct dot-notated keys and integer indices for arrays (e.g., "items.0.title"). Non-integer indices into lists will cause no change.
- Output type changed unexpectedly: If input was a JSON string, the output is a parsed object/list. Convert back to string later if a string is required.
- Got original JSON back: This happens when the path traverses a non-dict/list value or an invalid list index segment is used. Adjust the path or initialize the structure earlier.
- Empty key_path returned the value: This is by design. Provide a non-empty key_path to update within the JSON structure.
- Array index out of range: The node automatically extends arrays as needed. If you still see issues, ensure the parent path segments resolve to a list, not a dict or scalar.
- Invalid JSON string input: Ensure json_data is valid JSON when passed as a string. If invalid, parsing fails and the node returns the original data.