From 4ff337b2c40413019373e02302a83c2fe0bbea06 Mon Sep 17 00:00:00 2001
From: Alicia Sykes <alicia@omg.lol>
Date: Sat, 25 Jun 2022 19:43:07 +0100
Subject: [PATCH] =?UTF-8?q?=E2=9C=A8=20Adds=20helper=20function=20to=20det?=
 =?UTF-8?q?ermine=20address=20type?=
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---
 src/utils/address-type-checker.ts | 60 +++++++++++++++++++++++++++++++
 1 file changed, 60 insertions(+)
 create mode 100644 src/utils/address-type-checker.ts

diff --git a/src/utils/address-type-checker.ts b/src/utils/address-type-checker.ts
new file mode 100644
index 0000000..7e3fcc3
--- /dev/null
+++ b/src/utils/address-type-checker.ts
@@ -0,0 +1,60 @@
+/** 
+ * Helper functions to determine if a string is a valid web address,
+ * and what type of address it is: URL, IPv4, IPv6 or none of those.
+ */
+
+export type AddressType = 'ipV4' | 'ipV6' | 'url' | 'err' | 'empt';
+
+/* Checks if a given string looks like a URL */
+const isUrl = (value: string):boolean => {
+  const urlRegex= new RegExp(''
+    + /(?:(?:(https?|ftp):)?\/\/)/.source
+    + /(?:([^:\n\r]+):([^@\n\r]+)@)?/.source
+    + /(?:(?:www\.)?([^/\n\r]+))/.source
+    + /(\/[^?\n\r]+)?/.source
+    + /(\?[^#\n\r]*)?/.source
+    + /(#?[^\n\r]*)?/.source
+  );
+  return urlRegex.test(value);
+};
+
+/* Checks if a given string looks like an IP Version 4 Address */
+const isIpV4 = (value: string): boolean => {
+  const ipPart = '(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)';
+  const ipV4Regex = new RegExp(`^${ipPart}.${ipPart}.${ipPart}.${ipPart}$`);
+  return ipV4Regex.test(value);
+};
+
+/* Checks if a given string looks like an IP Version 6 Address */
+const isIPv6 = (value: string): boolean => {
+  const components = value.split(':');
+  
+  if ((components.length < 2 || components.length > 8) ||
+    ((components[0] !== '' || components[1] !== '')
+      && !components[0].match(/^[\da-f]{1,4}/i))
+  ) return false;
+
+  let numberOfZeroCompressions = 0;
+  for (let i = 1; i < components.length; ++i) {
+    if (components[i] === '') {
+      ++numberOfZeroCompressions;
+      if (numberOfZeroCompressions > 1) return false;
+      continue;
+    }
+    if (!components[i].match(/^[\da-f]{1,4}/i)) return false;
+  }
+  return true;
+};
+
+const isShort = (value: string): boolean => {
+  return (!value || value.length <=3);
+};
+
+/* Returns the address type for a given address */
+export const determineAddressType = (address: string): AddressType => {
+  if (isShort(address)) return 'empt';
+  if (isUrl(address)) return 'url';
+  if (isIpV4(address)) return 'ipV4';
+  if (isIPv6(address)) return 'ipV6';
+  return 'err';
+};