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c9d09a6 Dec 26, 2017
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Templates

The templates attributes allow you to inject your own expressions and code using JavaScript code or template literals in order to override entity attributes and state. Within the code / template literals, you have full access to the entity's state object, which allows you to access other properties such as last_changed, attributes.friendly_name, etc. The full set of objects available is shown below.

Additionally, extra_data_template attribute is always evaluated as a template without using templates attributes for it.

In order for a template to return "nothing", for example so that extra_data_template won't take space or allow showing show_last_changed - return null from your template. Note that null can only be returned using code format, as template literal format always returns a string.

Note that those are JavaScript templates evaluated in your browser, not Jinja2 templates which are evaluated server-side and use a different syntax.

Available variables

Global variables

Those variables allow one entity to set state / attribute based on another entity or some other "external" thing. Using those hurts UI performance, so use them only if you indeed want an entity to depend on something external.

hass - the hass object

entities - a map object from entity_id to state objects.

Local Variables

entity - the state object for the current entity. Note that if you are using device or context aware attributes then the object you get is already modified.

attributes attributes map of the current entity. Shortcut for entity.attributes.

attribute the original (non-template) value of the attribute being calculated by a template. When calculating state, _stateDisplay, or extra_data_template it will be undefined.

state the original (non-template) state of the entity.

Special attributes

There are two special template attributes:

  • state will override the entity state. Note that logic that applies visual state still applies. For example non-off motion sensor is displayed as detected. Changing the state template wouldn't prevent this logic from running.
  • _stateDisplay sets the final display string and prevents any visual state logic from running.

Formats

You can provide the template in two different formats.

  • If the template contains the word return it will be treated as raw JavaScript code.
  • Otherwise it will be treated as JavaScript template literal that returns a string.

Examples

homeassistant:
  customize:
    ...
    light.bedroom:
      templates:
        theme: >
          if (attributes.power_consumption > 10) return 'red'; else return 'default';
      extra_data_template: >
        "${attributes.power_consumption !== 0 ? (attributes.power_consumption + 'W') : ''}"
    light.kitchen:
      templates:
        # Uses global variable - might be slow.
        theme: >
          if (entities['light.bedroom'].state === 'on') return 'red'; else return 'default';
      extra_data_template: >
        if (entities['light.bedroom'].attributes.brightness > 30) return 'Yes'; else return null;

Display brightness (even if it is 0%)

homeassistant:
  customize:
    light.my_light:
      extra_data_template: ${Math.round(attributes.brightness || 0) / 2.55}%

Display brightness only if it exists and is non-zero:

homeassistant:
  customize:
    light.my_light:
      extra_data_template: >
        if (attributes.brightness) return Math.round(attributes.brightness / 2.55) + '%'; else return null;

Change 'on' state to 'activated':

homeassistant:
  customize:
    binary_sensor.my_sensor:
      templates:
        state: if (state === 'on') return 'activated'; else return state;
    binary_sensor.motion_sensor:
      templates:
        # null will make the regular state-based logic to run.
        _stateDisplay: if (state === 'on') return 'activated'; else return null;

Make a group that contains all on entities.

Note that the group itself must be preexisting, CustomUI can't create a new group.

Note this doesn't change group membership that the backend sees, so calling services on this group would only affect the original members.

homeassistant:
  customize:
    group.on_devices:
      templates:
        entity_id: return Object.keys(entities).filter(key => entities[key].state === 'on')