Mini-graph-card: Empty graph with entities without history states

[mihalken]

Describe the bug
Empty graph with entities without state history. A similar problem #41.

To Reproduce
Steps to reproduce the behavior:

1. Stop update entity state, exp., sensor.voltage1 by mqtt publish
2. Exclude entity in component recorder
3. Only in test hass! Clear entity history states. Call service recorder.purge with data {"keep_days": 0, "repack": true}.
4. Restart hass
5. Set state for entity, exp. for voltage = 12.3
6. Add mini-graph-card on view

type: custom:mini-graph-card
show:
  graph: bar
  labels: true
entities:
  - entity: sensor.volatge1
  - entity: sensor.volatge2
  - entity: sensor.volatge3

1. See empty graph

Expected behavior
Graph card show bars current entities state.

Screenshots

Home Assistant
Version: 0.93
Tested: 0.92.2

mini-graph-card
Version: v0.3.3

Additional context
I exclude domain sensor and include entities those that are needed off history. Because i have a lot sensors and i want to see only current value.

[kalkih]

Hey,
Thanks for the extensive report!
The graph is completely based on the entity history and will therefore not work without history data, (history data also includes the latest/current state), so this is kind of expected behaviour

Could possibly add a fallback to use the current state if no history is available.

Also, check out the bar-card, could possibly be used in place of this card for your use case
https://github.com/custom-cards/bar-card