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isPort

Checks whether a value is a valid TCP/UDP port number. A port is defined as an integer between 0 and 65535 (inclusive).

This helper never throws and never mutates input. It performs strict type checks and does not coerce strings or other values into numbers.

Signature

function isPort(value: unknown): value is number

Parameters

Name Data type Description
value unknown The value to check. Must be an integer between 0 and 65535 (inclusive) to return true.

Returns

A boolean:

  • true: If the value is an integer within the valid port range.
  • false: Otherwise.

Examples

isPort(0)        // true
isPort(80)       // true
isPort(65535)    // true

isPort(-1)       // false
isPort(70000)    // false
isPort(3.14)     // false
isPort("80")     // false
isPort(null)     // false

Notes

  • This helper does not coerce strings (for example, "80" is invalid).
  • This helper requires the value to be a primitive number.
  • Use normalizePort if you need to coerce values into ports.
  • Use validatePort if you need a Result<T> instead of a boolean.

Next up

isRegExp