D3 scatterplot project help

i have been slowly chuggin along with the scatterplot. The bar graph project really helped me understand a lot of how d3 works. I was doing pretty well with the scatter plot until i found the codepen drop down menu that is able to organize your code. I thought this was wonderful until i did it and now i get an error, ‘‘cannot read properties of null’’. ive never seen this before. I dont know if it is something i did or if something got re aranged when i did the javascript cleanup.

if someone can take a peak and let me know what i messed up.

Side not, ive been trying to look at people asking questions of projects ive already completed to see if i could help (i understand there is no way i could help anyone with but i wanted to feel like i was giving back for all the help i receive) and it is sooo challenging helping us. thank you to all the volunteers helping us beginners.

d3.json(
  "https://raw.githubusercontent.com/freeCodeCamp/ProjectReferenceData/master/cyclist-data.json"
).then((data) => {
  const w = 900;
  const h = 900;
  const padding = 70;

  let yearMin;
  let yearMax;
  let yearArr1;
  const yearFunc = () => {
    const yearArr = [];
    yearArr1 = yearArr;
    for (let i = 0; i < data.length; i++) {
      const tempYr = data[i].Year;
      const tempDate = new Date(tempYr, 0);
      yearArr.push(tempDate);
    }
    yearMin = d3.min(yearArr);
    yearMax = d3.max(yearArr);
  };
  yearFunc();

  const timeScale1 = d3
    .scaleTime()
    .domain([yearMin, yearMax])
    .range([padding, w - padding]);

  let timeMin;
  let timeMax;
  const timeFunc = () => {
    const timeArr = [];
    for (let i = 0; i < data.length; i++) {
      const tempTime = data[i].Seconds;
      const tempMin = Math.floor(tempTime / 60);
      const tempSec = tempTime % 60;
      const tempDate = new Date(2015, 0, 1, 0, tempMin, tempSec);
      timeArr.push(tempDate);
      const combined = [tempMin + ":" + tempSec];
    }

    timeMin = d3.min(timeArr);
    timeMax = d3.max(timeArr);
  };
  timeFunc();

  const timeScale2 = d3
    .scaleTime()
    .domain([timeMin, timeMax])
    .range([padding, h - padding]);

  const timeScale3 = d3
    .scaleTime()
    .domain([timeMin, timeMax])
    .range([h - padding, padding]);

  const svg = d3
    .select("body")
    .append("svg")
    .attr("width", w)
    .attr("height", h)
    .style("background-color", "gray");

  const tooltip = d3
    .select("body")
    .append("div")
    .data(data)
    .style("background-color", "white")
    .style("position", "absolute")
    .style("opacity", 0);
 //   .attr('id', 'tooltip');

  svg
    .selectAll("circle")
    .data(data)
    .enter()
    .append("circle")
    .attr("class", "dot")
    .attr("data-xvalue", (d, i) => {
      return new Date(d.Year, 0);
    })
    .attr("data-yvalue", (d, i) => {
      return new Date(
        2015,
        0,
        1,
        0,
        Math.floor(d.Seconds / 60),
        d.Seconds % 60
      );
    })
    .attr("fill", (d, i) => {
      if (d.Doping == "") {
        return "black";
      } else {
        return "red";
      }
    })
    .attr("r", 5)
    .attr("cx", (d, i) => {
      return timeScale1(new Date(d.Year, 0));
    })
    .attr("cy", (d, i) => {
      return timeScale2(
        new Date(2015, 0, 1, 0, Math.floor(d.Seconds / 60), d.Seconds % 60)
      );
    })
  .on('mouseover', (e,d)=>{
    tooltip.style('opacity', 1)
      .text((d,i)=>{return 'Text here'})
      .style("top", (event.pageY)+"px")
       .style("left",(event.pageX)+"px")
  })

  const xAxis = d3.axisBottom(timeScale1);
  const yAxis = d3.axisLeft(timeScale3).tickFormat(d3.timeFormat("%M:%S"));

  svg
    .append("g")
    .attr("id", "x-axis")
    .attr("transform", "translate(0," + (h - padding) + ")")
    .call(xAxis);

  svg
    .append("g")
    .attr("id", "y-axis")
    .attr("transform", "translate(" + padding + ", 0)")
    .call(yAxis);
});

i signed back in and the error went away. not sure what caused it or fixed it. maybe just something weird from my browser or something

I just ran it and it passed all the tests. Maybe you just need to refresh the page?