point-hijinks.ts

type Point = [number, number] & {__brand?: any};

type GridPoint = Omit<Point, "__brand"> & {__brand?: "GridPoint"};
type PixelPoint = Omit<Point, "__brand"> & {__brand?: "PixelPoint"};

const point: Point = [1, 2];
const gridPoint: GridPoint = [1, 2];
const pixelPoint: PixelPoint = [1, 2];

// Points receive all
const _0: Point = point;
const _1: Point = gridPoint;
const _2: Point = pixelPoint;

// Grid point rejects PixelPoint
const _3: GridPoint = point;
const _4: GridPoint = gridPoint;
// @ts-expect-error
const _5: GridPoint = pixelPoint;

// Grid point rejects PixelPoint
const _6: PixelPoint = point;
// @ts-expect-error
const _7: PixelPoint = gridPoint;
const _8: PixelPoint = pixelPoint;