Map with Regex Keys

mapGetFromRegexKeys.js

function getFromRegexKeys(key, map) {
  for (let [re, val] of map.entries()) {
    if (re.test(key)) {
      return val(key.match(re));
    }
  }
}

const map = new Map([
  [/^foo\/(.+)$/, matchResults => matchResults[1]],
  [/^bar\/(.+)\/(.+)\/(.+)$/, matchResults => matchResults[2]],
]);

getFromRegexKeys('foo/', map); // === undefined
getFromRegexKeys('foo/quuz', map); // === 'quuz'
getFromRegexKeys('bar/baz/qux/quz', map); // === 'qux'