[Feature Request] Enhance locale file detection to support Unicode LDML identifiers

[baohouse]

Background

In the locales folder, you put files of the message bundle, e.g. en-US.ts, zh-CN.json, or fr.js. The format is generally 2-letter language code (ISO 639-1), followed by base separator - or _, and then an optional 2-letter region code (ISO 3166-1 alpha-2). However, Filipino has a language code of fil, which is 3 letters (ISO 639-2). So naming a file fil.js will not get picked up.

The reason for this is that the code currently uses a regex that assumes 2-letter language code.

umi/packages/plugins/src/utils/localeUtils.ts

Lines 90 to 92 in 35be997

	const localeFileMath = new RegExp(
	`^([a-z]{2})${separator}?([A-Z]{2})?\.(js|json|ts)$`,
	);

Proposal

Enhance the code to use a regex that supports Unicode LDML. In addition to supporting 2 or 3-letter language code (e.g. zh, fil, en), it allows for optional script tag, so sr-Latn and sr-Cyrl (Serbian written in Latin and Cyrillic respectively) would be supported, and the region code can either be 2 letters or 3 digits, e.g. es-419 which is Spanish as spoken in Latin America.

Additional context

There is ietf-language-tag-regex library which provides a regex to match on IETF BCP 47 which is the basis for Unicode LDML.

[Jinbao1001]

what about use tl_PH?