Little example of creating a coloured terminal progress bar in Dart.

terminal_progress_bar.dart

import 'dart:io' show stdout;

Future<void> main() async {
  print('\n\x1b[38;5;39mBUILDING CODE\x1b[0m');
  for (int j = 0; j < 3; j++) {
    for (int i = 0; i <= 100; i++) {
      drawProgressBar(i / 100.0, 20);
      await Future.delayed(const Duration(milliseconds: 25));
    }
  }
  stdout.write('\n');
}

void drawProgressBar(double amount, int size) {
  final limit = (size * amount).toInt();
  stdout.write(
    '\r\x1b[38;5;75;51m' +
        String.fromCharCodes(List.generate(size, (int index) {
          if (index < limit) {
            return 0x2593;
          }
          return 0x2591;
        })) +
        '\x1b[0m',
  );
}