JSON: Merge¶
Merges two JSON objects into a single object. Supports shallow merge (json2 overwrites json1 at the top level) and deep merge (nested objects are combined recursively while non-object values are overwritten by json2). If inputs are provided as JSON strings, they are parsed automatically.
Usage¶
Use this node when you need to combine configuration objects, augment default data with overrides, or consolidate two JSON structures. Choose 'shallow' to overwrite only top-level keys, or 'deep' to recursively merge nested dictionaries. Place it after nodes that produce JSON data or JSON strings, and before any node that consumes the merged result.
Inputs¶
| Field | Required | Type | Description | Example |
|---|---|---|---|---|
| json1 | True | WILDCARD | First JSON object (or JSON string) to merge. Typically the base or default data. | {"api": {"timeout": 10, "retries": 2}, "features": {"beta": false}} |
| json2 | True | WILDCARD | Second JSON object (or JSON string) to merge. Values here overwrite or extend json1 depending on the merge mode. | {"api": {"timeout": 20}, "features": {"beta": true}} |
| merge_mode | True | CHOICE | How to merge the two objects. 'shallow' overwrites top-level keys from json2. 'deep' recursively merges nested objects while overwriting non-object values with json2. | deep |
Outputs¶
| Field | Type | Description | Example |
|---|---|---|---|
| merged_data | WILDCARD | The merged JSON object. When deep merging, nested dictionaries are combined; otherwise json2 overwrites top-level keys from json1. | {"api": {"timeout": 20, "retries": 2}, "features": {"beta": true}} |
Important Notes¶
- Input flexibility: If json1 or json2 are strings, the node attempts to parse them as JSON. Invalid or empty strings parse to an empty object for merging.
- Type requirement for merging: Merging applies to dictionaries (objects). If either input is not a dictionary after parsing, the node returns json2 as-is.
- Deep vs shallow behavior: Deep merge only combines nested objects (dictionaries). Lists and primitive values are not merged element-wise; json2 values overwrite json1 values for those keys.
- Default mode: The default merge_mode is 'deep'. Set to 'shallow' if you only want top-level overwrites.
- Key conflicts: On conflicts, json2 takes precedence.
Troubleshooting¶
- Output is unchanged or unexpected: Ensure both inputs are valid JSON objects (not arrays or primitives). If one input is not an object, the node returns json2.
- Lists are not combined: This node does not perform element-wise list merges. Convert lists to objects with meaningful keys or handle list merging upstream.
- Invalid JSON string input: If a string fails to parse, it is treated as an empty object. Validate your JSON strings or use a validation node beforehand.
- Nested data not merging: Verify merge_mode is set to 'deep'. In 'shallow' mode, only top-level keys are considered.