LinkChecker and better linksToSkip function (#23001)

* LinkChecker and better linksToSkip function

Part of #1253

* try now

* escaped

* make sure it skips all non-english links

* feedbacked

script/check-english-links.js

@@ -52,7 +52,7 @@ program
 // Skip non-English content.
 const languagesToSkip = Object.keys(libLanguages)
   .filter((code) => code !== 'en')
-  .map((code) => `${root}/${code}`)
+  .map((code) => new RegExp(`${root}/${code}`))
 
 // Skip deprecated Enterprise content.
 // Capture the old format https://docs.github.com/enterprise/2.1/
@@ -66,7 +66,19 @@ const config = {
   recurse: !program.opts().dryRun,
   silent: true,
   // The values in this array are treated as regexes.
-  linksToSkip: [enterpriseReleasesToSkip, ...languagesToSkip, ...excludedLinks],
+  linksToSkip: linksToSkipFactory([enterpriseReleasesToSkip, ...languagesToSkip, ...excludedLinks]),
+}
+
+// Return a function that can as quickly as possible check if a certain
+// href input should be skipped.
+// Do this so we can use a `Set` and a `iterable.some()` for a speedier
+// check. The default implementation in Linkinator, if you set
+// the `linksToSkip` config to be an array, it will, for every URL it
+// checks turn that into a new regex every single time.
+function linksToSkipFactory(regexAndURLs) {
+  const set = new Set(regexAndURLs.filter((regexOrURL) => typeof regexOrURL === 'string'))
+  const regexes = regexAndURLs.filter((regexOrURL) => regexOrURL instanceof RegExp)
+  return (href) => set.has(href) || regexes.some((regex) => regex.test(href))
 }
 
 main()