Timeout less than 1000 ms will fail on IPhone 17-IOS 26

[guspaz0]

i was developing a quick TCP port scanner feature and realized that in IOS if i put a timeout less than 1000 ms, the socket fails automatically.

import net from 'net';
import { Platform } from 'react-native';
import { ConnectionOptions } from 'react-native-tcp-socket/lib/types/Socket';

export const createSocket = async (
  options: ConnectionOptions
) => {
  try {
    const socket = new net.Socket();
    return await new Promise<net.Socket>(async (resolve, reject) => {
      socket?.on('error', (err: any) => {
        if (socket) socket?.destroy();
        reject(err)
      });
      socket?.on('close', () => {
        if (socket) socket?.destroy();
      });
      socket?.on('timeout', () => {
        if (socket) socket?.destroy();
      });
      socket?.on('connect', () => {
        resolve(socket);
      });
      socket?.connect({
        ...options,
        ...Platform.select({
          android: {
            interface: 'wifi',
          },
          ios: {
            connectTimeout: 1000, // if you set this less than 1000 will fail
          },
        }),
      });
    });
  } catch (e) {
    //continue
    console.log(e);
  }
};

On Android 13 phisical device works after 333 ms connectTimeout, is a safe treshold. in IOS everything 999 below will instantly trigger 'error' event.