extract method

@override List extract(dynamic input)

Process input and extract necessary data.

• Note: the output is usually passed to the next extractor in the chain.

Implementation

@override
List extract(input) {
  final srcInputs = _prepareInputSource(input);
  var idx = 0;
  if (index < 0) {
    idx = srcInputs.length + index;
  } else {
    idx = index;
  }
  if (idx >= 0 && idx < srcInputs.length) {
    return [srcInputs[idx]];
  } else {
    return [];
  }
}