Hiding password in Settings UX

[ArikC]

I accept a username/password in the settings ux for my clockface, but would like to replace the displayed text **** when looking at the settings UX.

I believe the correct way to do this is via the renderItem option -- but can't find an example.

<TextInput
   title="Password"  
   label="Password"
   renderItem={ (value) => {
      return "<Text>*****</Text>";
      }
    }
    settingsKey="password"
              />

Does anyone have a sample that shows the right format of the JSX to return in the renderItem function?