What is the type signature of the main exported function?

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

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

It accepts an optional Options object and returns a Promise that resolves to a number representing the available TCP port.

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

• port — number | Iterable<number> — A preferred port or iterable of preferred ports
• exclude — Iterable<number> — Ports that should not be returned
• reserve — boolean (default: false) — Reserve the port for the lifetime of the process
• host — string — The host on which port resolution should be performed

The Options type also extends Omit<ListenOptions, 'port'>, which allows additional Node.js server listen options like ipv6Only.

FOLLOW_UPS:

• How does the exclude option work internally?
• What happens when a port is reserved vs. not reserved?
• How does portNumbers() helper function work?