Deno.consoleSize - Deno documentation
function Deno.consoleSize
consoleSize(): { columns: number; rows: number; }

Gets the size of the console as columns/rows.

const { columns, rows } = Deno.consoleSize();

This returns the size of the console window as reported by the operating system. It's not a reflection of how many characters will fit within the console window, but can be used as part of that calculation.

Return Type

{ columns: number; rows: number; }