Will hass.states.set work in JS templates?

[il77781]

Hello
Trying to implement this thing:

variables:
  fault:
    value: " [[[ if (variables.cond16 && variables.cond17) hass.states.set('sensor.fan_fault', '5', { 'fault' : '5' }) ]]] "
    force_eval: true

However, when the conditions are met, the card displays the following error:

ButtonCardJSTemplateError
TypeError: hass.states.set is not a function in 'if (variables.cond16 && variables.cond17) hass.states.set('sensor.fan_fault', '5', { 'fault' : '5' })'

Is it even possible to use hass.states.set in JS templates, or are there any syntax errors?

[RomRider]

Why would you want to set a state which is only front-end and local to the browser?
I have not implemented that with the new "proxy" as I don't see a use case for that but maybe you can help me understand?

[il77781]

state which is only front-end and local to the browser

I may not have fully understood this phrase... The state value set using hass.states.set is not saved in the state machine?

[RomRider]

No, it's never sent to the backend, it stays local to the browser until a new backend state update is pushed to the frontend and erases the value you added.

[il77781]

In my case, I would like to set not even a state, but an attribute...
So, I already have an entity, but it lacks one attribute that I would like to use later to change the appearance of the button-card...
Under certain conditions, this attribute would take on a specific value, and the appearance of the button-card would depend on this value. The key point is that this value needs to be "remembered," possibly for an extended period, which is why button-card variables are not suitable...
Yes, of course, I could solve this problem in a different way: create an additional Home Assistant Helper (for example, input number) and then change its value using a "standard" service (input_number.set_value)...
But I don't want to create anything additional...
I would like to avoid creating new entities, but rather add a new attribute to an existing entity. I have not found a better way than using hass.states.set (although I am not sure if this method is correct, as I have not tried it before). Yes, it may be a "unhealthy" desire on my part to store all data in such a "compact" and organized manner. I just wanted to confirm if this is possible. But if this is not possible (or you consider it incorrect due to the separation of frontend and backend functionality), then no problem - I will do it differently...

[RomRider]

Modifying hass.states is local to the browser, not shared with backend or even between 2 browsers and doesn't trigger card updates so I don't think your approach is the right one.
Since this PR #1095, writing hass.states is not possible anymore. I could add it, but I don't think it's a good idea.

[il77781]

So, let's say I have 3 attributes: {a: 1, b: 2, c:3}. If I add a new attribute, d:4, will the new backend state update not only overwrite the attributes a, b, and c, but also completely erase the attribute d?

[RomRider]

For an additional attribute, not 100% sure it would be erased, but pretty sure though. Also, even a browser refresh would delete the attribute as writing directly a state in the browser is not persisted anywhere. It only lives while the page is opened.

[il77781]

It turns out that the same method (I'm not sure about the correct terminology) hass.states.set can (theoretically) be executed both in the frontend and in the backend? However, in the case of button-card, it is executed in the frontend and has no effect on the backend and the state machine... Now it seems much clearer... In this case, there may be no point in using hass.states... Thank you for your clarification! I will try to solve this issue in a different way...

[RomRider]

There is no way to set hass.states in the backend. hass.states is the result of aggregating all the entities states in the frontend under one object (it is the case for all the cards in the frontend), and hass.states[entity].state is same as calling states(entity) or state_attr(entity, attr) in a jinja template in the backend.
In home assistant's backend you can't write an entity's state directly either.