FA-96443 / Phone number formatting / Member archive

Vanity keypad translator: seven-symbol numbers are accepted · case 03

"555-FAKE" formats as a partial number.

Member previewVariant 3 · 3 implementations · 7 checks per implementation

Case contract

Uppercase. Digits are kept, letters map to keypad digits (ABC2 DEF3 GHI4 JKL5 MNO6 PQRS7 TUV8 WXYZ9), spaces, hyphens, dots and parentheses are ignored and anything else returns None. At least ten symbols are needed; symbols after the tenth may only be letters (vanity overflow) and are dropped. Return the first ten digits as "DDD-DDD-DDDD".

Why this case matters

Vanity numbers printed in advertising are translated before dialing or storing; a wrong keypad table dials a stranger.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
too short	`"555-325-3"`	`null`	Failed

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