Method isPortInUseEx

src/tcpportscanner.ts:102–128

(port: number, host: string, avoid: Set<number>)

     */
    private static SeqNumber = 0;
    public static isPortInUseEx(port: number, host: string, avoid: Set<number>): Promise<boolean> {
        const seq = TcpPortScanner.SeqNumber++;
        const tries = TcpPortScanner.getLocalHostAliases();
        // We could have launched all tests at once and waited on a Promise.all but that fails on Linux
        // Have seen cases where it steps on itself. In the same try, it will give an EADDRINUSE and a listen
        // will succeed. Doing one at a time avoids that but that Linux behavior is strange indeed
        return new Promise<boolean> (async (resolve) => {
            if (avoid && avoid.has(port)) {
                resolve(true);
                return;
            }
            for (const host of tries) {
                try {
                    const inUse = await TcpPortScanner.isPortInUse(port, host, seq);
                    if (inUse) {
                        resolve(true);
                        return;
                    }
                }
                catch (e) {
                    resolve(true);
                    return;
                }
            }
            resolve(false);
        });
    }

    /**
     * Scan for free ports (no one listening) on the specified host.