createPrefixPhoneMetadata

Description#

Builds a CngxPhoneMetadata adapter from a region keyed prefix map, so a consumer declares the prefixes that matter instead of hand-writing the region branch and the matching closure.

The adapter resolves the line type by longest matching prefix: the matcher with the most matched leading digits wins, so a specific '0820' fixed-line rule beats a broader '08' mobile rule. Ties resolve to mobile (it is the decisive case auto mask alternation cares about). An unknown region or no matching prefix returns 'unknown', keeping the length-based fallback.

It still ships no numbering data - the caller supplies every prefix - so it is sugar over an inline adapter, not a replacement for a real metadata library like libphonenumber-js.

providePhoneMetadata(
  createPrefixPhoneMetadata({
    DE: { mobile: [/^1[567]/] },
    AT: { mobile: ['650', '660', '664', '676', '699'] },
  }),
);