Sensor

A room’s reading: a temperature or humidity sensor.*, read with the humidity and battery sensors on the same device. Read-only.

Quick example

import { useHaSensor } from "@dashhaus/core";
import { fmt1 } from "@dashhaus/core/entities";

/** A room's temperature, with the humidity and battery sensors on the same device. */
export function RoomReading() {
  const { entity } = useHaSensor("sensor.bedroom_temperature", {
    humidityEntityId: "sensor.bedroom_humidity",
    batteryEntityId: "sensor.bedroom_battery",
  });
  if (entity.state === "unavailable") return <p>{entity.name}: no reading</p>;
  return (
    <p>
      {entity.name}: {entity.temperature == null ? "—" : `${fmt1(entity.temperature)}${entity.unit}`}
      {entity.humidity != null && `, ${fmt1(entity.humidity)}% humidity`}
      {entity.battery != null && entity.battery < 20 && " (battery low)"}
    </p>
  );
}

Home Assistant gives each measurement its own entity. The hook reads the companions you name and puts them on one SensorEntity, so a card shows the room, not three sensors.

Component

<HaSensor> is useHaSensor as a component that draws nothing of its own. It takes every option of the hook as a prop, and hands the hook’s result to its child function. Use it where hooks can’t go, such as one per item of a list.

entityIdstring

The Home Assistant entity id.

children(live: HaSensorResult) => ReactNode

Draws the hook's result. The component itself draws nothing.

Hook

useHaSensor(entityId: string, options?: HaSensorOptions): HaSensorResult

One live, read-only sensor for any UI: the primary sensor composed with its humidity and battery companions.

It reads the sensor and its companions, its area, and today’s history of the temperature and the humidity companion. outdoor marks a sensor outside, where indoor comfort words don’t apply.

Options

humidityEntityId?string

Optional companion entity with `device_class: humidity`.

batteryEntityId?string

Optional companion entity with `device_class: battery`.

name?string

Overrides Home Assistant's friendly name.

area?string

Overrides the area Home Assistant's registries resolve for the entity.

outdoor?boolean

lastSeen?string

Overrides when the entity was last reachable, shown while it is unavailable.

unit?"°C" | "°F"

history?SensorHistory

Host-owned history override; when omitted, today's history is read from Home Assistant.

loadHistory?boolean

Set false to skip the Home Assistant history read.

Returns

entitySensorEntity

historySensorHistory

entity: SensorEntity

entityIdstring

The Home Assistant entity id.

namestring

Usually the room it measures.

area?string

Its area: the `area` option, else the one Home Assistant's registries resolve; none when neither has one.

state"unavailable" | "ok"

temperature?number

humidity?number

Relative humidity in percent. Omit for temperature-only sensors.

unit"°C" | "°F"

outdoor?boolean

Outdoor sensors skip the indoor comfort reading.

battery?number

Battery level in percent, for battery-powered sensors.

lastUpdated?string

lastSeen?string

While it is unavailable, when it was last reachable: the `lastSeen` option, else what Home Assistant reports.

history: SensorHistory

Today, from Home Assistant’s recorder, kept up to date by every change since. Pass history to supply your own, or loadHistory={false} to skip the read.

temperatureReading[]

Hourly readings for today: a value, "unavailable", or null for hours still ahead.

humidity?Reading[]

currentHournumber

Every temperature

A sensor’s domain doesn’t say what it measures, so the selector reads each one’s device_class.

import { HaSensor, useHaSelector } from "@dashhaus/core";
import type { HaSnapshot } from "@dashhaus/core";
import { fmt1 } from "@dashhaus/core/entities";

/** Every temperature sensor: a sensor's domain says nothing of what it measures, so read its device class. */
const temperatureIds = (snapshot: HaSnapshot) =>
  Object.values(snapshot.entities)
    .filter((entity) => entity.entity_id.startsWith("sensor.") && entity.attributes.device_class === "temperature")
    .map((entity) => entity.entity_id)
    .sort()
    .join(" ");

export function AllTemperatures() {
  const ids = useHaSelector(temperatureIds).split(" ").filter(Boolean);
  return (
    <ul>
      {ids.map((id) => (
        <li key={id}>
          <HaSensor entityId={id} loadHistory={false}>
            {({ entity }) => (
              <>
                {entity.name}: {entity.temperature == null ? "—" : `${fmt1(entity.temperature)}${entity.unit}`}
              </>
            )}
          </HaSensor>
        </li>
      ))}
    </ul>
  );
}

Tasks

Today’s high and low

import { useHaSensor } from "@dashhaus/core";
import { fmt1 } from "@dashhaus/core/entities";

/** Today's high and low so far, from the hourly readings the hook reads from Home Assistant's recorder. */
export function HighLow({ entityId }: { entityId: string }) {
  const { entity, history } = useHaSensor(entityId);
  const readings = history.temperature.filter((reading): reading is number => typeof reading === "number");
  if (readings.length === 0) return <p>{entity.name}: no readings yet today</p>;
  return (
    <p>
      {entity.name} today: {fmt1(Math.min(...readings))} to {fmt1(Math.max(...readings))}
      {entity.unit}
    </p>
  );
}

history.temperature has one reading per hour: a number, "unavailable", or null for hours ahead and before the first reading.

In a skin

Orb’s HaSensorTile and Field’s HaSensorModule are useHaSensor above each skin’s card. They take the hook’s options as props, plus their own:

import { HaSensorTile } from "@dashhaus/orb";
import { HaSensorModule } from "@dashhaus/field";

export function OrbRoom() {
  return <HaSensorTile entityId="sensor.living_room_temperature" humidityEntityId="sensor.living_room_humidity" />;
}

export function FieldOutside() {
  return <HaSensorModule entityId="sensor.outside_temperature" outdoor footprint="compact" />;
}

Orb

entityIdstring

Primary sensor, normally the temperature entity for this device.

showControl?boolean

Compact only. false removes the inline reading, shows its value in its place, and makes the row open the detail sheet. Default true.

footprint?CardFootprint

Card footprint. The skin's stylesheet sets the heights; the three names are the shared vocabulary.

defaultOpen?boolean

defaultAction?undefined

Field

entityIdstring

Primary sensor, normally the temperature entity for this device.

footprint?FieldFootprint

defaultOpen?boolean

Open the detail panel on first render (stories).

Every state of both is in Storybook: Orb and Field.