Extract Field

Overview

The Extract Field node reads a single value from an incoming object using a dot-path expression (e.g. user.profile.displayName) and passes that value downstream. It is used to narrow a large object down to one field before passing it to a node that expects a scalar or a simpler shape. When the path does not exist or the input is not an object, execution is routed to the error output so downstream nodes can handle missing-field cases explicitly.

Configuration

Field	Type	Required	Description
path	string	Yes	Dot-path expression that identifies the field to extract (e.g. result.scores[0].value). Supports bracket notation for array indices.
fallback	string	No	Value returned on the output port when the path resolves to undefined. When omitted and the path is missing, execution routes to error instead.
strict	boolean	No	When true, a null value at the resolved path is also treated as missing and routes to error. Defaults to false.

Inputs

Port	Type	Description
input	object	The source object from which the field is extracted. Must be a JSON-serialisable object; primitives and arrays at the root level cause an error.

Outputs

Port	Type	Description
output	any	The extracted field value. Type matches whatever is stored at the resolved path (string, number, boolean, object, or array).
error	object	Emitted when the path cannot be resolved and no fallback is configured, or when strict is true and the resolved value is null. Contains message and path fields describing the failure.

Example

{
  "nodeType": "extract_field",
  "config": {
    "path": "battle.result.winner.handle",
    "fallback": "unknown",
    "strict": false
  }
}