formatDouble method

String formatDouble(
  1. int decimalPlaces, {
  2. bool showTrailingZeros = true,
})

Formats this double to a string with a specified number of decimal places.

Optionally removes trailing zeros after the decimal point when showTrailingZeros is false.

Examples when showTrailingZeros is false:

  • 15.00 → "15"

  • 15.50 → "15.5"

  • 15.05 → "15.05"

  • decimalPlaces: The number of decimal places to format to.

  • showTrailingZeros: Whether to keep trailing zeros (default: true).

Example:

15.0.formatDouble(2); // '15.00'
15.0.formatDouble(2, showTrailingZeros: false); // '15'
15.5.formatDouble(2, showTrailingZeros: false); // '15.5'
15.05.formatDouble(2, showTrailingZeros: false); // '15.05'

Implementation

String formatDouble(int decimalPlaces, {bool showTrailingZeros = true}) {
  if (isNaN) return 'NaN';
  if (isInfinite) return isNegative ? '-∞' : '∞';
  // toStringAsFixed throws RangeError for decimalPlaces < 0 or > 20
  final int clampedPlaces = decimalPlaces.clamp(0, 20);
  final String result = toStringAsFixed(clampedPlaces);

  if (showTrailingZeros || clampedPlaces == 0) {
    return result;
  }

  // Remove trailing zeros, then remove trailing decimal point if present
  return result.replaceAll(_trailingZerosRegex, '').replaceAll(_trailingDecimalPointRegex, '');
}