JSON: Filter¶
Filters JSON data based on a key-value condition. Accepts a list (array) of objects and returns only those objects whose specified key matches the given value according to the selected mode (equals, contains, starts_with, ends_with). If the input is a JSON string, it will be parsed before filtering.
Usage¶
Use this node when you need to narrow down an array of JSON objects to only those matching a simple key-value rule. Typical workflow: load or produce JSON data (often an array of objects), then filter it by a specific field and comparison mode before passing the result to subsequent processing nodes.
Inputs¶
| Field | Required | Type | Description | Example |
|---|---|---|---|---|
| json_data | True | WILDCARD | The JSON data to filter. Should be an array (list) of objects. If provided as a string, it will be parsed. | [{"status":"active","id":1},{"status":"inactive","id":2}] |
| filter_key | True | STRING | The object key to evaluate for each item in the array. | status |
| filter_value | True | WILDCARD | The value to compare against for the chosen key. Used differently depending on filter_mode. | active |
| filter_mode | True | ENUM: equals\|contains\|starts_with\|ends_with | How to compare the item's value for filter_key with filter_value. equals uses exact equality; contains, starts_with, and ends_with perform string-based checks. | equals |
Outputs¶
| Field | Type | Description | Example |
|---|---|---|---|
| filtered_data | WILDCARD | The filtered JSON data. Typically a list of objects matching the filter condition. If filtering is not applicable, the original data is returned. | [{"status":"active","id":1}] |
Important Notes¶
- Input type: The node expects json_data to be a list (array) of objects. If it's not a list, the data is returned unchanged.
- String parsing: If json_data is a string, it will be parsed as JSON before filtering.
- Key requirement: If filter_key is empty, no filtering is done and the original data is returned.
- Missing keys: Objects without the specified filter_key are ignored (not included in the result).
- Comparison behavior: equals uses exact equality without converting types; contains, starts_with, and ends_with compare using string representations of values.
- Error handling: On parsing or runtime errors, the node logs the error and returns the original input unmodified.
Troubleshooting¶
- No filtering occurs: Ensure json_data is an array of objects and filter_key is not empty.
- Unexpected matches with 'equals': Check for type mismatches (e.g., number vs string). equals does not coerce types.
- Contains/starts/ends not matching: These modes are string-based and case-sensitive. Convert values to a consistent case beforehand if needed.
- Got original data back: This happens if input wasn't a list, filter_key was empty, or an internal error occurred. Validate your input format.
- JSON string input fails: Verify the JSON string is valid and represents an array of objects.