What is the type signature of the main exported function?

The main exported function getPort has the following type signature:

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

This is defined in [index.d.ts:L66].

The function accepts an optional Options object and returns a Promise<number> — the promised port number. The Options type is defined in [index.d.ts:L3-L65] and includes properties like:

• port: A preferred port or iterable of preferred ports
• exclude: Ports to exclude from consideration
• reserve: Whether to lock the port for the process lifetime
• host: The specific host to check availability on

FOLLOW_UPS:

• What does the portNumbers() helper function do?
• How does the reserve option work internally?
• What error handling occurs when no ports are available?