HasTileAt = function (tileX, tileY, layer)
{
    if (IsInLayerBounds(tileX, tileY, layer))
    {
        var tile = layer.data[tileY][tileX];

        return (tile !== null && tile.index > -1);
    }
    else
    {
        return false;
    }
}
Checks if there is a tile at the given location (in tile coordinates) in the given layer. Returns
false if there is no tile or if the tile at that location has an index of -1.

@function Phaser.Tilemaps.Components.HasTileAt
@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 {Phaser.Tilemaps.LayerData} layer - The Tilemap Layer to act upon.

@return {?boolean} Returns a boolean, or null if the layer given was invalid.