1 files changed, 100 insertions, 0 deletions
diff --git a/vanilla/node_modules/tldts-core/src/domain.ts b/vanilla/node_modules/tldts-core/src/domain.ts
new file mode 100644
index 0000000..640d33e
--- /dev/null
+++ b/vanilla/node_modules/tldts-core/src/domain.ts
@@ -0,0 +1,100 @@
+import { IOptions } from './options';
+
+/**
+ * Check if `vhost` is a valid suffix of `hostname` (top-domain)
+ *
+ * It means that `vhost` needs to be a suffix of `hostname` and we then need to
+ * make sure that: either they are equal, or the character preceding `vhost` in
+ * `hostname` is a '.' (it should not be a partial label).
+ *
+ * * hostname = 'not.evil.com' and vhost = 'vil.com'      => not ok
+ * * hostname = 'not.evil.com' and vhost = 'evil.com'     => ok
+ * * hostname = 'not.evil.com' and vhost = 'not.evil.com' => ok
+ */
+function shareSameDomainSuffix(hostname: string, vhost: string): boolean {
+  if (hostname.endsWith(vhost)) {
+    return (
+      hostname.length === vhost.length ||
+      hostname[hostname.length - vhost.length - 1] === '.'
+    );
+  }
+
+  return false;
+}
+
+/**
+ * Given a hostname and its public suffix, extract the general domain.
+ */
+function extractDomainWithSuffix(
+  hostname: string,
+  publicSuffix: string,
+): string {
+  // Locate the index of the last '.' in the part of the `hostname` preceding
+  // the public suffix.
+  //
+  // examples:
+  //   1. not.evil.co.uk  => evil.co.uk
+  //         ^    ^
+  //         |    | start of public suffix
+  //         | index of the last dot
+  //
+  //   2. example.co.uk   => example.co.uk
+  //     ^       ^
+  //     |       | start of public suffix
+  //     |
+  //     | (-1) no dot found before the public suffix
+  const publicSuffixIndex = hostname.length - publicSuffix.length - 2;
+  const lastDotBeforeSuffixIndex = hostname.lastIndexOf('.', publicSuffixIndex);
+
+  // No '.' found, then `hostname` is the general domain (no sub-domain)
+  if (lastDotBeforeSuffixIndex === -1) {
+    return hostname;
+  }
+
+  // Extract the part between the last '.'
+  return hostname.slice(lastDotBeforeSuffixIndex + 1);
+}
+
+/**
+ * Detects the domain based on rules and upon and a host string
+ */
+export default function getDomain(
+  suffix: string,
+  hostname: string,
+  options: IOptions,
+): string | null {
+  // Check if `hostname` ends with a member of `validHosts`.
+  if (options.validHosts !== null) {
+    const validHosts = options.validHosts;
+    for (const vhost of validHosts) {
+      if (/*@__INLINE__*/ shareSameDomainSuffix(hostname, vhost)) {
+        return vhost;
+      }
+    }
+  }
+
+  let numberOfLeadingDots = 0;
+  if (hostname.startsWith('.')) {
+    while (
+      numberOfLeadingDots < hostname.length &&
+      hostname[numberOfLeadingDots] === '.'
+    ) {
+      numberOfLeadingDots += 1;
+    }
+  }
+
+  // If `hostname` is a valid public suffix, then there is no domain to return.
+  // Since we already know that `getPublicSuffix` returns a suffix of `hostname`
+  // there is no need to perform a string comparison and we only compare the
+  // size.
+  if (suffix.length === hostname.length - numberOfLeadingDots) {
+    return null;
+  }
+
+  // To extract the general domain, we start by identifying the public suffix
+  // (if any), then consider the domain to be the public suffix with one added
+  // level of depth. (e.g.: if hostname is `not.evil.co.uk` and public suffix:
+  // `co.uk`, then we take one more level: `evil`, giving the final result:
+  // `evil.co.uk`).
+  return /*@__INLINE__*/ extractDomainWithSuffix(hostname, suffix);
+}