Visualize Data with a Bar Chart - Related to Tooltip issue

Tell us what’s happening:
Hello! I am doing D3 challenge and stuck with tooltip function.
Could you help me why I cannot pass the " TooltipTests" No. 1 & 2?
I think I might misunderstand the user story…
Thank you in advance!! :blush:

TooltipTests 1. I can mouse over an area and see a tooltip with a corresponding id=“tooltip” which displays more information about the area
TooltipTests 2. My tooltip should have a “data-date” property that corresponds to the “data-date” of the active area.

Your code so far

  svg.append('title')
        .text((d,i) => barDate[i] + ' : ' + barGdp[i])
        .attr('data-date', (d, i) => dataset[i][0])
        .attr("id", "tooltip");

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.109 Safari/537.36.

Link to the challenge: