GetTileAt = function (tileX, tileY, nonNull, layer)
{
    if (IsInLayerBounds(tileX, tileY, layer))
    {
        var tile = layer.data[tileY][tileX] || null;

        if (!tile)
        {
            return null;
        }
        else if (tile.index === -1)
        {
            return nonNull ? tile : null;
        }
        else
        {
            return tile;
        }
    }
    else
    {
        return null;
    }
}
Gets a tile at the given tile coordinates from the given layer.

@function Phaser.Tilemaps.Components.GetTileAt
@since 3.0.0

@param {number} tileX - X position to get the tile from (given in tile units, not pixels).
@param {number} tileY - Y position to get the tile from (given in tile units, not pixels).
@param {boolean} nonNull - For empty tiles, return a Tile object with an index of -1 instead of null.
@param {Phaser.Tilemaps.LayerData} layer - The Tilemap Layer to act upon.

@return {Phaser.Tilemaps.Tile} The tile at the given coordinates or null if no tile was found or the coordinates were invalid.