static int trimmedFileLiveValue_defaultInterval = 1000;

static SimpleLiveValue<S> trimmedFileLiveValue(final File f, fS defaultValue) {
  final SimpleLiveValue<S> lv = stringLiveValue(S, trim(loadTextFile(f, defaultValue)));
  lv.onChange(r { saveTextFile(f, lv!) });
  doEvery(trimmedFileLiveValue_defaultInterval, r {
    lv.set(trim(loadTextFile(f, defaultValue)));
  });
  ret lv;
}