addNewLine static method

void addNewLine({
  1. required String filePath,
  2. required String refLine,
  3. required String newLine,
})

Implementation

static void addNewLine({
  required String filePath,
  required String refLine,
  required String newLine,
}) {
  File file = File(filePath);
  List<String> lines = file.readAsLinesSync();
  final index = lines.lastIndexWhere((element) => element.contains(refLine));
  lines.insert(index + 1, newLine);
  file.writeAsStringSync(lines.join('\n'));
}