Calculate the midpoint between two points

JavaScript

const midpoint = (p1, p2) => [(p1.x + p2.x) / 2, (p1.y + p2.y) / 2]

TypeScript

interface Point {
  x: number
  y: number
}

const midpoint = (p1: Point, p2: Point): number[] => [(p1.x + p2.x) / 2, (p1.y + p2.y) / 2]