Input validation?

[BayssMekanique]

Are there recommendations for how to validate a Text Input field?  There seems be a lot of "magic" wrapped up into the settings fields and I'm not certain what hooks are available to change colors or display messages of any sort.

[LeiChat]

I'm interested to know how anyone has implemented validation.
I would like to limit the user input to 15 characters and if possible validate using a regular expression.
If the input is invalid, how do you let the user know? Can you amend a label in the Settings page?

[Gondwana]

This is a good question. The best way that I've come up with is to include a 'status' element in the settings:

        <TextInput
          label="Status"
          placeholder="Not created."
          settingsKey="accountStatus"
          disabled="true"
        />

You can update the text displayed therein from companion/index.js; eg:

settingsStorage.setItem('accountStatus',{'name':accountStatusMsg});

However, I've found that the element doesn't word-wrap, so I have to limit status messages to about 35 characters. The lack of dynamic word-wrapping kinda seems like a bug.

[LeiChat]

Thanks @Gondwana
Do you have to load the value the next time the companion loads or does the <TextInput> load the value from settingsStorage itself?

[Gondwana]

To my experience, once the text is stored in the setting, it will stick. The TextInput will grab it automatically in future.