isDoubleString function

IValidator isDoubleString({ String? message, })

Validates that the String can be parsed as a double (e.g. '123.45', '-1e3')

Usage Examples:

final doubleStringValidator = isDoubleString();
doubleStringValidator.validate("123.45");     // Valid
doubleStringValidator.validate("-1e3");        // Valid
doubleStringValidator.validate("12");          // Valid (int is also double)
doubleStringValidator.validate("not-a-number"); // Invalid

// For strict double-only validation
final strictDouble = all([$isString, isDoubleString(), not(isIntString())]);

Implementation

IValidator isDoubleString({String? message}) =>
    isType<String>() &
    validator(
      (value) => double.tryParse(value.trim()) != null,
      (value) => Expectation(
        message: message ?? 'a valid formatted double String',
        value: value,
        code: ExpectationCodes.valueFormatInvalid,
        data: {'format': 'double'},
      ),
    );