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export interface freePortOption {  hostname?: string;  transport?: "tcp";}
function random(min: number, max: number): number {  return Math.round(Math.random() * (max - min)) + min;}
/** * Determine if a port is available for using * Requires `--allow-net` flag * @param port  The port number to find: *              0 - 1023 WellKnownPorts *              1024 - 49151 RegisteredPorts *              49152 - 65535 Dynamicand/orPrivatePorts * @param options */export async function isFreePort(  port: number,  options: freePortOption = {},): Promise<boolean> {  try {    const listener = await Deno.listen({      port: port,      ...(options.hostname ? { hostname: options.hostname } : {}),      ...(options.transport ? { transport: options.transport } : {}),    });
    listener.close();
    return true;  } catch (err) {    if (err instanceof Deno.errors.AddrInUse) {      return false;    }
    throw err;  }}
/** * Found free port. * If the port is not available, returns the port * If the port is not available, returns a random available port * Requires `--allow-net` flag * @param port  The port number to find: *              0 - 1023 WellKnownPorts *              1024 - 49151 RegisteredPorts *              49152 - 65535 Dynamicand/orPrivatePorts * @param options */export async function getFreePort(  port: number,  options: freePortOption = {},): Promise<number> {  try {    const listener = await Deno.listen({      port: port,      ...(options.hostname ? { hostname: options.hostname } : {}),      ...(options.transport ? { transport: options.transport } : {}),    });
    listener.close();
    return port;  } catch (err) {    if (err instanceof Deno.errors.AddrInUse) {      const newPort = port <= 1023        ? random(0, 1023)        : port <= 49151          ? random(1024, 49151)          : random(49152, 65535);      return getFreePort(newPort, options);    }
    throw err;  }}