gistfile1.js

var fs = require('fs');
function readJsonFile(fileName) {
  var buf = fs.readFileSync(fileName);
  return JSON.parse(buf.toString('utf8'));
}
var deviceRegistry = readJsonFile('./.storage/core.device_registry')
var devices = deviceRegistry.data.devices;

var smokeDetectors = {};
for (var device of devices) {
  if (device.name === "First Alert (BRK Brands Inc) ZCombo Smoke and Carbon Monoxide Detector") {
    smokeDetectors[device.id] = {name: device.name_by_user}
  }
}

var entitiesRegistry = readJsonFile('./.storage/core.entity_registry')
var entities = entitiesRegistry.data.entities;

for (var entity of entities) {
  var entityDevice = smokeDetectors[entity.device_id];
  if (entityDevice) {
    var entityType;
    if (entity.device_class === "battery") {
      entityDevice.battery = entity;
    } else if (entity.entity_id.indexOf("alarm_level") > 0) {
      entityDevice.alarmLevel = entity;
    } else if (entity.entity_id.indexOf("alarm_type") > 0) {
      entityDevice.alarmType = entity;
    }
  }
}

var smokeDetectorsArr = Object.values(smokeDetectors);
console.log(`
binary_sensor:
 - platform: template
   sensors:`);
for (var idx in smokeDetectorsArr) {
  const smokeDetector = smokeDetectorsArr[idx];
  console.log(printConfig(idx, smokeDetector.name, smokeDetector.alarmLevel.entity_id, smokeDetector.alarmType.entity_id));
}
console.log(`homekit:
  auto_start: false
  entity_config:`);
for (var idx in smokeDetectorsArr) {
  const smokeDetector = smokeDetectorsArr[idx];
  console.log(printHomeKitConfig(idx, smokeDetector.name, smokeDetector.battery.entity_id));
}

function printConfig(idx, deviceName, alarmLevelSensorId, alarmTypeSensorId) {
  var template =
`     smoke_sensor_${idx}:
       unique_id: smoke_sensor_${idx}
       friendly_name: ${deviceName} 
       device_class: smoke
       value_template: >-
          {% if is_state('${alarmLevelSensorId}', '255') and is_state('${alarmTypeSensorId}', '1') %}
            smoke
          {% elif is_state('${alarmLevelSensorId}', '255') and is_state('${alarmTypeSensorId}', '2') %}
            co
          {% elif is_state('${alarmLevelSensorId}', '0') and is_state('${alarmTypeSensorId}', '12') %}
            test
          {% elif is_state('${alarmLevelSensorId}', '255') and is_state('${alarmTypeSensorId}', '13') %}
            idle
          {% endif %}
       icon_template: >-
          {% if is_state('${alarmLevelSensorId}', '255') and is_state('${alarmTypeSensorId}', '1') %}
            mdi:fire
          {% elif is_state('${alarmLevelSensorId}', '255') and is_state('${alarmTypeSensorId}', '2') %}
            mdi:cloud-outline
          {% elif is_state('${alarmLevelSensorId}', '0') and is_state('${alarmTypeSensorId}', '12') %}
            mdi:alert-octagram
          {% elif is_state('${alarmLevelSensorId}', '255') and is_state('${alarmTypeSensorId}', '13') %}
            mdi:smoke-detector
          {% endif %}
`
  return template;
}

function printHomeKitConfig(idx, name, batterySensorId) {
  var template = `
    binary_sensor.smoke_sensor_${idx}:
      linked_battery_sensor: ${batterySensorId}`
  return template;
}