Get tile bounds from XYZ

get-tile-bounds.ts

export function lngFromMercatorX(x: number): number {
    return x * 360 - 180;
}

export function latFromMercatorY(y: number): number {
    const y2 = 180 - y * 360;
    return 360 / Math.PI * Math.atan(Math.exp(y2 * Math.PI / 180)) - 90;
}

function getBounds(tileID: CanonicalTileID): [number, number, number, number] {
    const worldSize = Math.pow(2, tileID.z);

    const x1 = tileID.x / worldSize;
    const x2 = (tileID.x + 1) / worldSize;
    const y1 = tileID.y / worldSize;
    const y2 = (tileID.y + 1) / worldSize;

    // left, bottom, right, top
    return [
        lngFromMercatorX(x1),
        latFromMercatorY(y2),
        lngFromMercatorX(x2),
        latFromMercatorY(y1)
    ];
}