.. include:: /includes.txt

.. _workflow_states_pass:

==========
Pass state
==========

A Pass state (``"type": "Pass"``) passes its input to its output, without
performing work. Pass states are useful when constructing and debugging
state machines.

In addition to the common state fields, Pass states allow the following fields.

Result (Optional)
    Treated as the output of a virtual task to be passed to the next state,
    and filtered as specified by the ResultPath field (if present).

mapping (Optional)
    Specifies where (in the input) to place the "output" of the virtual task
    specified in Result. The input is further filtered as specified by the
    OutputPath field (if present) before being used as the state's output.
    For more information, see Input and Output Processing.

Parameters (Optional)
    Create a collection of key-value pairs that will be passed as input.
    Values can be static, or selected from the input with a path. For more
    information, see InputPath and Parameters.

Pass State Example

Here is an example of a Pass state that injects some fixed data into the
state machine, probably for testing purposes.

.. code-block:: json

  "example": {
    "type": "Pass",
    "result": {
      "hello": "world"
    },
    "mapping": {
      "output": "$.output"
    },
    "end": true
  }

Suppose the input to this state is the following.

.. code-block:: json

  {
    "example": "input"
  }

Then the output would be this.

.. code-block:: json

  {
    "example": "input",
    "output": {
      "hello": "world"
    }
  }