source: ps/trunk/binaries/data/mods/public/maps/random/rmgen/Area.js

/**
 * @file An Area is a set of Vector2D points and a cache to lookup membership quickly.
 */

function Area(points)
{
    this.points = deepfreeze(points);

    const mapSize = g_Map.getSize();

    this.cache = new Array(mapSize).fill(0).map(() => new Uint8Array(mapSize));
    for (const point of points)
        this.cache[point.x][point.y] = 1;
}

Area.prototype.getPoints = function()
{
    return this.points;
};

Area.prototype.contains = function(point)
{
    return g_Map.inMapBounds(point) && this.cache[point.x][point.y] == 1;
};

Area.prototype.getClosestPointTo = function(position)
{
    if (!this.points.length)
        return undefined;

    let closestPoint = this.points[0];
    let shortestDistance = Infinity;

    for (const point of this.points)
    {
        const currentDistance = point.distanceToSquared(position);
        if (currentDistance < shortestDistance)
        {
            shortestDistance = currentDistance;
            closestPoint = point;
        }
    }

    return closestPoint;
};