Conditional Card Template and Sensor Lacks State

[Brandon_Beierle]

Hi All,

I’m trying to create a conditional card that is present when a weather warning sensor (Environment Canada) is populated. I can’t make the state: or state_not: test to see if the sensor is populated. I recognize that I could make a template binary sensor, but that seems inefficient so I was trying to use a template in the conditional card conditions section.

This led me to another discovery - it seems like the value of the sensor when there is no warning is nothing. If I test for ‘is defined’ it is defined. If I test for ‘null’, it is not null. If I test for ‘none’, it is not none. “” and ‘’ give the same results. If I try ‘x{{ states(“sensor.warnings”) }}x’ in the template editor, I get ‘xx’, so it is not a single space or some other special character. The state is not ‘unknown’ either.

So, question 1 is can I use a template in the conditional card conditions, and question 2 is what state is this sensor in when it is not populated with data - even if I were to make a template binary sensor, I wouldn’t know how to test it.

Thanks in advance for your help!

[tom_l]

Test for string length > 0

[Brandon_Beierle]

Yeah, I got string+‘A’ = ‘A’ to work too. Thanks for that suggestion - it’s a bit more graceful.

Any idea if I can do that directly as a template in the conditional card, or does it need to be via a binary sensor?

Thanks again!

[tom_l]

The core Lovelace cards don’t support templates. However there are a couple of custom cards that enable it:

1. JINJA templates (you want this one):

Lovelace card-templater card (Jinja2 card templating in Lovelace!)

I had looked at the config-template card but, since I wanted to be able to reuse the Jinja2 templates I use in the rest of Home Assistant, I decided to see if I could create a card like that which could apply Jinja2 templates Lovelace cards. Introducing the card-templater card https://github.com/gadgetchnnel/lovelace-card-templater Installation This requires card-tools to be installed, check the link for details on installing this if you don’t have it installed. This card can either be instal…

2. JavaScript (included for completeness):

100% Templatable Lovelace Configurations

Lovelace Templates I’ve gone and made a crazy card that allows you to pretty much template anything in Lovelace for your card configurations using any information available on the frontend; states, attributes, user, etc. Want state/attribute-based icons? DONE! Want dynamic stacks; vertical vs horizontal based on user? DONE! Want OR conditionals? DONE! The list is pretty much endless and I’m sure you all will come up with some crazy stuff. Be sure to share. Go nuts! Enjoy!

[Brandon_Beierle]

Ok, great! Thanks for the insights. I hadn’t run across those cards before.

[iantrich (Ian)]

Be aware that using jinja2 templates causes a we socket connection to be opened for the backend to parse and evaluate it. If you use a lot of them, it can become a burden on your server and your frontend

[tom_l]

Thanks Ian, that’s good to know. I was thinking of changing my wind compass to jinja templates but now I’ll leave it as JavaScript.

[Brandon_Beierle]

Thanks Guys, binary sensors it is!