prefixLines function

List<String> prefixLines(String chunk, String label)

Prefixes every non-blank line of chunk with label.

label arrives already padded and coloured — ANSI escapes count toward string length, so padding here would misalign every prefix.

Returns the lines rather than printing them, so the caller decides where they go and a test can look at them.

Implementation

List<String> prefixLines(String chunk, String label) {
  return [
    for (final line in chunk.split('\n'))
      if (lastFrame(line) case final frame
          when frame.isNotEmpty && !isUnfinished(frame))
        '$label | $frame',
  ];
}