d3-tip-在工具提示中创建标题的问题

Question

I've successfully created a chart in a tooltip, by following this example: https://bl.ocks.org/maelafifi/ee7fecf90bb5060d5f9a7551271f4397 . But my problem is in creating a title, like so:

var tool_tip = d3.tip()
            .attr("class", "d3-tip")
            .offset([10, -50])
            .html(function(d){console.log(d); return "<p> Day: and hour:</p><div id='tipDiv'></div>";});
            //.html(function(d,i){console.log(d); return "<p>Distribution for all weeks at: Day: " + d.day + " and hour: " + d.hour +"</p><div id='tipDiv'></div>";}); 
            svg_sum.call(tool_tip);

I actually want to create the text that is commented out, but when looking in the console, it says that d is undefined. Additionally, I would like to use the information in d to offset the tooltip. My attempt can be seen here: http://bl.ocks.org/skov94/0c4befd23bcaeacb85c18c7a5484f95d

Answer 1

In your code, you have an argument d which you might have forgotten to pass in.

So, when calling the function, do something like:

tool_tip.show(day)