move out parseAddress & host2Buffer function from class.

src/lib/command.ts

@@ -1,6 +1,73 @@
 import {AddressType, CommandReplyType, CommandType} from "./constants.js";
 import ipaddr from 'ipaddr.js';
 
+function parseAddress(chunk: Buffer):[string, number] {
+    let address = [], port;
+    const addressType = chunk.readUint8(3);
+
+    switch (addressType) {
+        case AddressType.IPv4:
+            address.push(chunk.readUint8(4).toString());
+            address.push(chunk.readUint8(5).toString());
+            address.push(chunk.readUint8(6).toString());
+            address.push(chunk.readUint8(7).toString());
+            port = chunk.readUInt16BE(8);
+            return [address.join('.'), port];
+        case AddressType.Domain:
+            const domainLength: number = chunk.readUint8(4);
+            let i:number;
+            for(i = 5; i < 5 + domainLength; i++) {
+                address.push(String.fromCharCode(chunk.readUint8(i)));
+            }
+            port = chunk.readUInt16BE(i);
+            return [address.join(''), port];
+        case AddressType.IPv6:
+            let byteArray: number[] = [];
+            for(let i = 4; i < 20; i++) {
+                byteArray.push(chunk.readUint8(i));
+            }
+            const ipv6Addr = ipaddr.fromByteArray(byteArray);
+            port = chunk.readUInt16BE(20);
+            return [ipv6Addr.toString(), port];
+        default:
+            break;
+    }
+
+    return ['', 0];
+}
+
+function host2Buffer(chunk: Buffer, host: string): number {
+    let nextOffset: number = -1;
+    let offset = 4; // all command host started at index of 4
+    const addressType = chunk.readUint8(3);
+
+    switch (addressType) {
+        case AddressType.IPv4:
+            host.split('.').forEach((seg: string) => {
+                chunk.writeUint8(Number.parseInt(seg), offset++);
+            });
+            nextOffset = 8;
+            break;
+        case AddressType.Domain:
+            chunk.writeUint8(host.length, 4);
+            offset += 1;
+            [...host].forEach((c, i) => {
+                chunk.writeUint8(host.charCodeAt(i), offset++);
+            });
+            nextOffset = 4 + 1 + host.length;
+            break;
+        case AddressType.IPv6:
+            const bytes = ipaddr.parse(host).toByteArray();
+            bytes.map((byte) => {
+                chunk.writeUint8(byte, offset++);
+            });
+            nextOffset = 20;
+            break;
+    }
+
+    return nextOffset;
+}
+
 export class Command {
     public version: number;
     public commandType: CommandType;
@@ -14,38 +81,10 @@ export class Command {
         this.commandType = chunk.readUint8(1) as CommandType;
         this.addressType = chunk.readUint8(3) as AddressType;
 
-        [this.host, this.port] = this.parseAddress(chunk);
+        [this.host, this.port] = parseAddress(chunk);
     }
+}
 
-    private parseAddress(chunk: Buffer):[string, number] {
-        let address = [], port;
-        switch (this.addressType) {
-            case AddressType.IPv4:
-                address.push(chunk.readUint8(4).toString());
-                address.push(chunk.readUint8(5).toString());
-                address.push(chunk.readUint8(6).toString());
-                address.push(chunk.readUint8(7).toString());
-                port = chunk.readUInt16BE(8);
-                return [address.join('.'), port];
-            case AddressType.Domain:
-                const domainLength: number = chunk.readUint8(4);
-                let i:number;
-                for(i = 5; i < 5 + domainLength; i++) {
-                    address.push(String.fromCharCode(chunk.readUint8(i)));
-                }
-                port = chunk.readUInt16BE(i);
-                return [address.join(''), port];
-            case AddressType.IPv6:
-                let byteArray: number[] = [];
-                for(let i = 4; i < 20; i++) {
-                    byteArray.push(chunk.readUint8(i));
-                }
-                const ipv6Addr = ipaddr.fromByteArray(byteArray);
-                port = chunk.readUInt16BE(20);
-                return [ipv6Addr.toString(), port];
-            default:
-                break;
-        }
 
         return ['', 0];
     }
@@ -78,38 +117,9 @@ export class CommandReply {
         chunk.writeUint8(this.commandReplyType.valueOf(), 1);
         chunk.writeUint8(0, 2);
         chunk.writeUint8(this.addressType.valueOf(), 3);
-        const nextOffset: number = this.Host2Buffer(chunk, 4);
+        const nextOffset: number = host2Buffer(chunk, this.host);
         chunk.writeUInt16BE(this.port, nextOffset);
 
         return chunk;
     }
-
-    private Host2Buffer(chunk: Buffer, offset: number): number {
-        let nextOffset: number = -1;
-        switch (this.addressType) {
-            case AddressType.IPv4:
-                this.host.split('.').forEach((seg: string) => {
-                    chunk.writeUint8(Number.parseInt(seg), offset++);
-                });
-                nextOffset = 8;
-                break;
-            case AddressType.Domain:
-                chunk.writeUint8(this.host.length, 4);
-                offset += 1;
-                [...this.host].forEach((c, i) => {
-                   chunk.writeUint8(this.host.charCodeAt(i), offset++);
-                });
-                nextOffset = 4 + 1 + this.host.length;
-                break;
-            case AddressType.IPv6:
-                const bytes = ipaddr.parse(this.host).toByteArray();
-                bytes.map((byte) => {
-                    chunk.writeUint8(byte, offset++);
-                });
-                nextOffset = 20;
-                break;
-        }
-
-        return nextOffset;
-    }
 }