JavaScript

Determine Color from a Sensor Value

const value = Number.parseFloat(entity?.state);

if (Number.isNaN(value)) {
  return '#9E9E9E';
}

if (value < -20) {
  return '#87CEFA';
}

if (value < -5) {
  return '#4CAF50';
}

if (value < 0) {
  return '#FFEB3B';
}

return '#F44336';

Safely Access a Home Assistant Entity

const entityId = 'binary_sensor.wlan_2_4_ghz_status';
const state = hass.states[entityId]?.state ?? 'unknown';

const color =
  state === 'on'
    ? '#4CAF50'
    : state === 'off'
      ? '#F44336'
      : '#9E9E9E';

Event Listener for a Website

const button = document.querySelector('#start-button');

button?.addEventListener('click', () => {
  console.log('Start was clicked');
});

Safely Parse JSON

function parseJsonSafe(value) {
  try {
    return JSON.parse(value);
  } catch (error) {
    console.error('Invalid JSON:', error);
    return null;
  }
}