Better way to validate UUID strings

[maxsatula]

I would like to offer a better (more strict, paranoid) way to validate UUID strings, rather than just length check after hyphens are stripped (how can we be sure the hyphens were at the right places?)
I never used TypeScript, so my example is in pure JavaScript:

new RegExp( '^' + [8, 4, 4, 4, 12].map( l => `[0-9a-f]{${l}}` ).join('-') + '$' ).test(uuid)

I deliberately left case sensitivity on, demanding that UUID string passed in lowercase. However, if you think otherwise, obviously we can add i modifier to a regex (I would rather not).

Thank you

[maxsatula]

Also, a simpler, in my opinion, way to build a dashed string from a buffer:

Array.prototype.map.call(buffer.toString('hex'), (c, i) => ([8,12,16,20].includes(i) ? '-' : '') + c ).join('')