What is the type signature of the main exported function?

The main exported function getPort has the following type signature [index.d.ts:L66]:

export default function getPort(options?: Options): Promise<number>;

It's an async function that accepts an optional Options object and returns a Promise<number> representing the available port number.

The Options type is defined in [index.d.ts:L3-L65] and includes:

• port: A preferred port number or iterable of preferred ports
• exclude: An iterable of port numbers to exclude from consideration
• reserve: A boolean (default false) to reserve the port for the process lifetime
• host: A string specifying the host (IPv4 or IPv6 address) for port resolution
• Additional options inherited from Node.js ListenOptions

FOLLOW_UPS:

• How does the exclude option filter ports?
• What does the reserve option actually do?
• What happens when no ports are available?