spacebar-remap.json

{
  "title": "Change spacebar",
  "rules": [
    {
      "description": "Change spacebar to right-option if pressed with other keys (Post spacebar when pressed alone)",
      "manipulators": [
        {
          "type": "basic",
          "from": {
            "key_code": "spacebar",
            "modifiers": {
              "optional": [
                "any"
              ]
            }
          },
          "to": [
            {
              "key_code": "right_option"
            }
          ],
          "to_if_alone": [
            {
              "key_code": "spacebar"
            }
          ]
        }
      ]
    }
  ]
}