tooltip = {
chart
const tooltip = d3.select("body").append("div")
.attr("class", "svg-tooltip-heat")
.style("position", "absolute")
.style("visibility", "hidden")
.text("Im a circle!!!!!!!!!!!!!!!")
.style("font-size", "18px")
.style("color", "red")
.attr("font-family", "monospace");
d3.selectAll("#rectangle")
.on("mouseover", function(d){
console.log('da d',d);
return tooltip.style("visibility", "visible").style("top", 80 + (d.Row) * gridSize*1.2+"px").style("left", 20+(d.Column) * gridSize*1.1+"px").text(days(d.Date)+", "+d.Row+", "+d.Column);
})
.on("mouseout", function(){
return tooltip.style("visibility", "hidden");
});
}