getPairX method

X? getPairX(
  1. P pair
)

Implementation

X? getPairX(P pair) {
  if (pair == null) {
    return null;
  } else if (pair is List) {
    return pair[0];
  } else if (pair is Map) {
    var val = findKeyValue((pair as Map<String, dynamic>), xKeys, true);
    return val as X?;
  } else if (pair is Pair) {
    return pair.a;
  } else if (pair is String) {
    return pair.split(stringPairDelimiterPattern)[0] as X;
  } else {
    throw UnsupportedError(
        "Can't handle pair of type ${pair.runtimeType}: $pair");
  }
}