MapOutlinetype

A map's outlines, drawn where they are drawn: a region in a box carried into it, outlying islands in a box carried into theirs, everything else where the projection put it.

Kept against the map itself, so a page that redraws on every pick parses its paths once. Canada's are 76,000 points and cost 16ms to walk, a third of a frame, on a keystroke.

import type { MapOutline } from "@johnmorrisdotca/chizu";

type MapOutline = {
    rings: MapRing[];
    anchor: [
        number,
        number
    ] | null;
};

import WORLD from "@johnmorrisdotca/chizu/world";
import { mapOutlines, type MapOutline } from "@johnmorrisdotca/chizu";

const japan: MapOutline = mapOutlines(WORLD)[WORLD.regions.findIndex((region) => region.code === "JP")]!;
console.log(japan.rings.length > 1, japan.anchor !== null);
// true true

true true