1 files changed, 79 insertions, 0 deletions
diff --git a/vanilla/node_modules/tldts-core/src/is-valid.ts b/vanilla/node_modules/tldts-core/src/is-valid.ts
new file mode 100644
index 0000000..03cc384
--- /dev/null
+++ b/vanilla/node_modules/tldts-core/src/is-valid.ts
@@ -0,0 +1,79 @@
+/**
+ * Implements fast shallow verification of hostnames. This does not perform a
+ * struct check on the content of labels (classes of Unicode characters, etc.)
+ * but instead check that the structure is valid (number of labels, length of
+ * labels, etc.).
+ *
+ * If you need stricter validation, consider using an external library.
+ */
+
+function isValidAscii(code: number): boolean {
+  return (
+    (code >= 97 && code <= 122) || (code >= 48 && code <= 57) || code > 127
+  );
+}
+
+/**
+ * Check if a hostname string is valid. It's usually a preliminary check before
+ * trying to use getDomain or anything else.
+ *
+ * Beware: it does not check if the TLD exists.
+ */
+export default function (hostname: string): boolean {
+  if (hostname.length > 255) {
+    return false;
+  }
+
+  if (hostname.length === 0) {
+    return false;
+  }
+
+  if (
+    /*@__INLINE__*/ !isValidAscii(hostname.charCodeAt(0)) &&
+    hostname.charCodeAt(0) !== 46 && // '.' (dot)
+    hostname.charCodeAt(0) !== 95 // '_' (underscore)
+  ) {
+    return false;
+  }
+
+  // Validate hostname according to RFC
+  let lastDotIndex = -1;
+  let lastCharCode = -1;
+  const len = hostname.length;
+
+  for (let i = 0; i < len; i += 1) {
+    const code = hostname.charCodeAt(i);
+    if (code === 46 /* '.' */) {
+      if (
+        // Check that previous label is < 63 bytes long (64 = 63 + '.')
+        i - lastDotIndex > 64 ||
+        // Check that previous character was not already a '.'
+        lastCharCode === 46 ||
+        // Check that the previous label does not end with a '-' (dash)
+        lastCharCode === 45 ||
+        // Check that the previous label does not end with a '_' (underscore)
+        lastCharCode === 95
+      ) {
+        return false;
+      }
+
+      lastDotIndex = i;
+    } else if (
+      !(/*@__INLINE__*/ (isValidAscii(code) || code === 45 || code === 95))
+    ) {
+      // Check if there is a forbidden character in the label
+      return false;
+    }
+
+    lastCharCode = code;
+  }
+
+  return (
+    // Check that last label is shorter than 63 chars
+    len - lastDotIndex - 1 <= 63 &&
+    // Check that the last character is an allowed trailing label character.
+    // Since we already checked that the char is a valid hostname character,
+    // we only need to check that it's different from '-'.
+    lastCharCode !== 45
+  );
+}