How to conditionally add brightness parameter to a single light action

[distant void]

I have an automation that ends with a single light.turn_on action

• action: light.turn_on
  metadata: {}
  data: {}
  target:
  entity_id: light.example_light
  I would like to conditionally add a brightness value to its data, behind a simple template
  data:
  brightness_pct: "{{ a_brightness_variable }}"
  but only if it's an integer (has been defined as an integer), otherwise an expected float error pops up.

How can I go around doing that? I can't duplicate the light turn on action since it's got quite a few branches and other (non optional) parameters set on the way.

[covert briar]

You can template the entire value of the data key as a dictionary:

action: light.turn_on
target:
  entity_id: light.example
data: |
  {{ {"brightness_pct": a_brightness_variable} if a_brightness_variable is integer else {} }}

[distant void]

ohh damn I did not realise that and it's absolutely perfect

[left relic]

the other option would be to duplicate the light.turn_on action - have one with the brightness, one without, and use a conditional statement (if) to pick which one to run. (edit: ah, you explained why that would be difficult)