1 files changed, 23 insertions, 0 deletions
diff --git a/src/tools/ipv4-subnet-calculator/ipv4-subnet-calculator.models.ts b/src/tools/ipv4-subnet-calculator/ipv4-subnet-calculator.models.ts
new file mode 100644
index 0000000..7a515ca
--- /dev/null
+++ b/src/tools/ipv4-subnet-calculator/ipv4-subnet-calculator.models.ts
@@ -0,0 +1,23 @@
+export { getIPClass };
+
+function getIPClass({ ip }: { ip: string }) {
+  const [firstOctet] = ip.split('.').map(Number);
+
+  if (firstOctet < 128) {
+    return 'A';
+  }
+  if (firstOctet > 127 && firstOctet < 192) {
+    return 'B';
+  }
+  if (firstOctet > 191 && firstOctet < 224) {
+    return 'C';
+  }
+  if (firstOctet > 223 && firstOctet < 240) {
+    return 'D';
+  }
+  if (firstOctet > 239 && firstOctet < 256) {
+    return 'E';
+  }
+
+  return undefined;
+}