validate method Null safety

void validate(
  1. ValidationContext context,
  2. dynamic input
)

Validates the input value.

Subclasses override this method to provide validation behavior.

input is the value being validated. If the value is invalid, the reason is added to context via ValidationContext.addError.

Additional information about the validation event and the attribute being evaluated is available in context. in context.

This method is not run when input is null.

The type of input will have already been type-checked prior to executing this method.

Implementation

void validate(ValidationContext context, dynamic input) {
  switch (type!) {
    case ValidateType.absent:
      {}
      break;
    case ValidateType.present:
      {}
      break;
    case ValidateType.comparison:
      {
        final expressions = context.state as List<ValidationExpression>;
        expressions.forEach((expr) => expr.compare(context, input));
      }
      break;
    case ValidateType.regex:
      {
        final regex = context.state as RegExp;
        if (!regex.hasMatch(input as String)) {
          context.addError("does not match pattern ${regex.pattern}");
        }
      }
      break;
    case ValidateType.oneOf:
      {
        final options = context.state as List<dynamic>;
        if (options.every((v) => input != v)) {
          context.addError(
              "must be one of: ${options.map((v) => "'$v'").join(",")}.");
        }
      }
      break;
    case ValidateType.length:
      {
        final expressions = context.state as List<ValidationExpression>;
        expressions.forEach(
            (expr) => expr.compare(context, (input as String).length));
      }
      break;
  }
}