Fixed.fromNum constructor

Fixed.fromNum(num amount, { int scale = 16, })

Creates a Fixed scale value from a double or integer value and stores the value with the given scale.

scale defaults to 16 if not passed.

This method will throw AmountTooLargeException if the scale is > 20 or the absolute value is greater than 10^21 This method will clip the no. of decimal places to 20.

final value = Fixed.fromNum(1.2345, scale: 2);
print(value) -> 1.23

For a decimal amount we throw a AmountTooLargeException if an amount is larger 10^21 is passed in. An AmountTooLargeException will be thrown if the scale > 20. If you need larger numbers then use one of the alternate constructors.

Implementation

Fixed.fromNum(num amount, {this.scale = 16}) {
  _checkScale(scale);

  final decoder = FixedDecoder(
    pattern: '#.#',
    groupSeparator: ',',
    decimalSeparator: '.',
  );

  /// toStringAsFixed is limited to a max of 20 decimal places
  try {
    final fixed = amount.toStringAsFixed(scale);
    if (fixed.contains('e')) {
      throw AmountTooLargeException('The amount must be less than 10^20');
    }
    final decimalAndScale = decoder.decode(fixed, scale);
    minorUnits = decimalAndScale.value;
    // ignore: avoid_catching_errors
  } on RangeError catch (_) {
    throw AmountTooLargeException('The maximum scale for num is 20.');
  }
}