Allow initial value for text_sensor

[ViToni]

Component name

text_sensor

Link to component documentation on our website

https://esphome.io/components/text_sensor/

Describe the enhancement

DISCLAIMER: Maybe I'm misusing some components as this is my first time contact with ESPHome.

I'd like the text_sensor to allow an initial value.
My current workaround doesn't look like the right way to do it:

   on_boot:
    - priority: 600
      then:
        - delay: 1s
        # workaround as there is no initial value for this sensor
        - lambda: id(wifi_signal_icon).publish_state("\U000F05A9"); // wifi icon (full) 

Use cases

When state of a text_sensor is updated by other sensors it might miss an initial value while the other sensor has no initial value change.

My use case is a text_sensor holding a wifi signal strength indicator as icon:

sensor:
  - platform: wifi_signal
    name: WiFi Signal
    id: wifi_signal_db
    update_interval: 60s
    on_value:
      # ---- Text sensor to expose the current WiFi status icon ----
      lambda: |-
        // computed current wifi status icon
        auto computed_icon = "";

        int8_t rssi = id(wifi_signal_db).state;

        // based on the logic in https://github.com/esphome/esphome/blob/7394cbf77329f3b5a035e5ce334c9ac0ae19818c/esphome/components/wifi/wifi_component.cpp#L417
        if (rssi >= -50) {
          computed_icon = "\U000F05A9"; // wifi icon (full)
        } else if (rssi >= -65) {
          computed_icon = "\U000F0922"; // 2 bars
        } else  if (rssi >= -85) {
          computed_icon = "\U000F091F"; // 1 bar
        } else {
          computed_icon = "\U000F092B"; // 0 bars with alert
        }

        // publish only on change
        if (id(wifi_signal_icon).state != computed_icon) {
          id(wifi_signal_icon).publish_state(computed_icon);
        }

text_sensor:
  - platform: template
    id: wifi_signal_icon
    name: "WiFi Signal Strength Icon"

The code works expect in the initial case where there is no wifi_signal_db yet. To cover this initial period a way to provide an initial value would be useful.

Anything else?

No response

[github-actions[bot]]

🏷️ I've automatically added the component: text_sensor label to help categorize this feature request.

[nagyrobi]

If this is intended to be used in LVGL to update a label, I suggest to set the label initially in LVGL to \U000F05A9, as it will be overwritten when the sensor updates.

[ViToni]

No LVGL for me. It's on an ESP8266.
My somehow improved version is to move the "default value" from on_boot to on_connect in the wifi section.