minted gives you real types for the values you'd usually keep in a String and hope for the
best: emails, IBANs, phone numbers, and more. Every type is built on parse, don't validate, so an
instance can only exist if it's well-formed, the same guarantee Uri gives you for URLs. Once you
hold an Email, it is a valid email. No more carrying "is this string actually valid?" three
functions deep.
It's pure Dart, so it runs everywhere Dart does: Flutter apps, servers, CLIs, and the web. And every type wears the same small API, so learning one teaches you the rest.
Install
dart pub add minted
A quick taste
final email = Email.parse('Jane.Doe@Example.COM');
email.value; // 'Jane.Doe@example.com' (domain lower-cased for you)
email.domain; // 'example.com'
Email.tryParse('not-an-email'); // null, nothing thrown
What's in the box
| Type | What it guarantees | Standard |
|---|---|---|
Email |
a well-formed address, domain lower-cased | RFC 5322 |
Iban |
structure, country length, and the mod-97 checksum | ISO 13616 |
PhoneNumber |
a valid number, stored in E.164 | ITU-T E.164 |
Digit / Digits |
a single digit 0-9, or an iterable sequence of them |
building block |
Everything checks the real standard, not just the shape: Iban actually runs the mod-97 checksum
and Email the full RFC 5322 grammar. A regex that only looks right isn't enough.
One shape, every type
Learn one type and you've learned them all. Each one gives you:
Type.tryParse(input)returns the value, ornullwhen the input isn't validType.parse(input)returns the value, or throwsMintedFormatException(it extendsFormatException, so your existingon FormatExceptionhandlers still catch it)- value equality:
a == bcompares content, not identity - a canonical form to read back (
.valueon most types,.asStringonDigits), normalised on parse so equal values really are equal - an assembly factory for parts you already trust (
fromComponents,from, orof) - getters that fit the type:
email.domain,iban.checkDigits,phone.nationalNumber
More examples
final iban = Iban.parse('gb29 nwbk 6016 1331 9268 19');
iban.value; // 'GB29NWBK60161331926819' (compact)
iban.countryCode; // 'GB'
iban.checkDigits; // (first: Digit, second: Digit)
iban.formatted; // 'GB29 NWBK 6016 1331 9268 19' (grouped paper form)
final phone = PhoneNumber.parse('0 655 5705 76', region: 'FR');
phone.value; // '+33655570576' (E.164)
phone.type; // PhoneNumberType.mobile
phone.nationalNumber; // Digits(655570576) (an Iterable<Digit>)
phone.telUri; // tel:+33655570576
// national-format input takes a region hint; international ('+…') input doesn't:
PhoneNumber.tryParse('0 655 5705 76'); // null (no region given)
// build from parts you already trust (throws if they don't form a valid whole):
Iban.fromComponents(countryCode: 'GB', bban: 'NWBK60161331926819'); // computes the check digits
Email.fromComponents(localPart: 'jane', domain: 'example.com');
PhoneNumber.fromComponents(countryCode: '33', nationalNumber: Digits.parse('655570576'));
Why "parse, don't validate"?
A validator takes a String, checks it, and hands the same String back, so every function
downstream has to trust the check happened, or re-check it. A parser takes a String and returns a
different type that can only exist if the input was well-formed. Validity becomes a fact of the
type system: checked once, carried everywhere.
That's what int.parse and Uri.parse already do, and it's what every minted type does for its
domain. String email, String phone, String name are three interchangeable, mixed-up-able
parameters; Email, PhoneNumber, PersonName are not. (Named after Alexis King's essay.)
Scope: what minted covers, and what it doesn't
minted fills the gap where no clean value type exists. It doesn't re-model what the SDK (Uri,
DateTime, BigInt) or strong packages (money2, uuid, intl) already cover well. Where a good
package already solves a piece, minted wraps it rather than reinventing: the email grammar, the IBAN
registry, and phone metadata all come from established packages.
IBAN country coverage comes from iban_validator, which
tracks recent adoptions and includes some countries not yet in the formal ISO registry. You can
check a given country in its
data file.
Roadmap
xEmail(RFC 5322)xIban(ISO 13616, mod-97)xPhoneNumber(E.164)xDigit/Digits(numeric building blocks)Bic,CreditCardNumber(Luhn),Isbn,Ean/Gtin- Later: ISO code lists, bounded numerics, opt-in JSON /
fpdart/ Flutter companions
Contributing
Issues and pull requests are welcome. If you're adding a type, hold it to the shared value-type
contract (parse-don't-validate, a private constructor, MintedFormatException, value equality) and
bring the official standard test vectors along.
License
Libraries
- minted
- Well-modelled value types (domain primitives) for entities usually left as a
raw
String: email, IBAN, and more.