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Telixon

How Telixon works

Google libphonenumber’s metadata is compiled ahead of time into a single deterministic finite automaton (DFA), stored as binary tables. Every answer about a phone number comes from that automaton.

Parsing

Section titled “Parsing”

Parsing is a walk over the automaton, one digit per step. The state the walk ends on determines the region, the number type, whether the number is valid, and how to format it.

const number = parsePhoneNumber('+1 (415) 555-0132');
// the walk has already happened


number.getRegion(); // 'US'
number.getNumberType(); // 'FIXED_LINE_OR_MOBILE'
number.isValid(); // true

Validity

Section titled “Validity”

A number is valid when the walk ends on an accepting state. That is the whole definition. Everything else is a classified failure, returned as a typed value:

parsePhoneNumber('5550132', { defaultRegion: 'US' }).getValidationError();
// { kind: 'POSSIBLE_LOCAL_ONLY' }

Seven digits form a US number that connects only inside its own area. The walk ends on a state that records exactly that. The nine variants are in ValidationError.

Parser and controller consistency

Section titled “Parser and controller consistency”

parsePhoneNumber walks the automaton once, over a whole string. An input controller walks it again on every keystroke, over the value as it stands. It is the same walk, which makes their answers agree by construction. A controller can hand you a PhoneNumber at any moment, mid-typing.

const controller = createInternationalInputController();
controller.setValue('+1 (415) 555-0132');


controller.getPhoneNumber().formatE164(); // '+14155550132'
parsePhoneNumber('+1 (415) 555-0132').formatE164(); // '+14155550132'

Consequences

Section titled “Consequences”