.regex()

Passes when pattern.hasMatch(value) is true. The pattern is a RegExp, so its flags apply and an invalid pattern throws where the validator is built rather than where it runs. It is not anchored for you: RegExp(r'[0-9]') accepts 'abc1def'. Add ^ and $ when the whole string has to match.

Signature

StringValidator<O> regex(RegExp pattern, {String? message, MessageBuilder? messageBuilder})

Parameters

Parameter	Type	Meaning
pattern	RegExp	The pattern. Use a raw string literal inside RegExp(...). params['pattern'] holds its source.
message	String?	Replaces the default error message.
messageBuilder	MessageBuilder?	Builds the message from the issue. message wins when both are given. See Message builders.

Issue

Code invalidPattern. Default message: value must match the pattern ^[a-z0-9-]+$, naming the pattern. value is replaced by the field name when there is one.

Code generation

@MatchRegex(r'...'), with the optional flags caseSensitive, multiLine, unicode and dotAll. The generator builds the RegExp and passes flags that differ from the default. Put the annotation on the constructor parameter or the field.

Example

Hand-written

final slug = l.string().regex(RegExp(r'^[a-z0-9-]+$'));

Generated

@MatchRegex(r'^[a-z0-9-]+$') required String slug,
// l.string().regex(RegExp(r'^[a-z0-9-]+$')).required()
@MatchRegex(r'^[a-z]+$', caseSensitive: false) required String word,
// l.string().regex(RegExp(r'^[a-z]+$', caseSensitive: false)).required()

slug.validate(input)+1-1

1. +valid: 'hello-world'
2. -invalid: 'Hello World'value must match the pattern ^[a-z0-9-]+$

Flags and anchoring:

l.string().regex(RegExp(r'^[a-z]+$', caseSensitive: false)).validate('Hello').isValid;
l.string().regex(RegExp(r'[0-9]')).validate('abc1def').isValid;

true
true