AWS Step Function JsonMerge new data

Question

The intrinsic function States.JsonMerge works to add a new, static json in the data simulator. So this works in the Parameters in the data simulator to add the newKey to all the incoming input of the state:

{
  "input.$": "States.JsonMerge($, { \"newKey\": 1 }, false)"
}

However, in an actual State Machine definition, it rejects that.

At the least, this seems to show an issue with either the data simulator or the state machine definition rules.

The question is there a way to do such an operation of adding a new "hard coded" json object like the data simulator allows and format it correctly for the state machine?

Answer 1

Add a hardcoded key and hardcoded value to the input:

{
  "input.$": "States.JsonMerge($, States.StringToJson('{\"newkey\":1}'), false)"
}

Add a hardcoded key and a *substituted* value to the input:

{
  "input.$": "States.JsonMerge($, States.StringToJson(States.Format('\\{\"newkey\":\"{}\"\\}', $.myValue)), false)"
}