freeCodeCamp/curriculum/challenges/english/04-data-visualization/d3-dashboard/part-064.md

6.5 KiB

id title challengeType dashedName
5d8a4cfbe6b6180ed9a1ca1d Part 64 0 part-64

--description--

Next, chain the enter() function to the selection.

The enter function identifies elements that need to be added when the data array is longer than the selection array. This is why you wanted the selectAll to be an empty array before.

In this case, the twitter-circles selection has a length of 0, and the data array has a length of 9. So nine elements will be added when you use append in the next step.

--hints--

test-text

assert(/\.data\(data\)\s*\.enter\s*\(\s*\)/g.test(code));

--seed--

--before-user-code--

<!DOCTYPE html>
<html>
  <head>
    <title>D3 Dashboard</title>
    <style>
      body {
        background-color: #ccc;
        padding: 100px 10px;
      }

      .dashboard {
        width: 980px;
        height: 500px;
        background-color: white;
        box-shadow: 5px 5px 5px 5px #888;
        margin: auto;
        display: flex;
        align-items: center;
      }
    </style>
  </head>

  <body>
    <div class="dashboard"></div>
  </body>
</html>

--seed-contents--

<script>
  const data = [ 
    { year: 2012, followers: { twitter: 2594, tumblr:  401, instagram:   83 }},
    { year: 2013, followers: { twitter: 3049, tumblr:  440, instagram:  192 }},
    { year: 2014, followers: { twitter: 3511, tumblr:  415, instagram:  511 }},
    { year: 2015, followers: { twitter: 3619, tumblr:  492, instagram: 1014 }},
    { year: 2016, followers: { twitter: 4046, tumblr:  543, instagram: 2066 }},
    { year: 2017, followers: { twitter: 3991, tumblr:  701, instagram: 3032 }},
    { year: 2018, followers: { twitter: 3512, tumblr: 1522, instagram: 4512 }},
    { year: 2019, followers: { twitter: 3274, tumblr: 1989, instagram: 4715 }},
    { year: 2020, followers: { twitter: 2845, tumblr: 2040, instagram: 4801 }}
  ];
</script>
<script>
  const svgMargin = 70,
    svgWidth = 700,
    svgHeight = 500,
    twitterColor = '#7cd9d1',
    tumblrColor = '#f6dd71',
    instagramColor = '#fd9b98';

  const lineGraph = d3.select('.dashboard')
    .append('svg')
    .attr('width', svgWidth)
    .attr('height', svgHeight);

  const yScale = d3.scaleLinear()
    .domain([0, 5000])
    .range([svgHeight - svgMargin, svgMargin]);

  const xScale = d3.scaleLinear()
    .domain([2012, 2020])
    .range([svgMargin, svgWidth - svgMargin]);

  const yAxis = d3.axisLeft(yScale)
    .ticks(6, '~s');

  const xAxis = d3.axisBottom(xScale)
    .tickFormat(d3.format(''))
    .tickPadding(10);

  lineGraph.append('g')
    .call(yAxis)
    .attr('transform', `translate(${svgMargin}, 0)`)
    .style('font', '10px verdana');

  lineGraph.append('g')
    .call(xAxis)
    .attr('transform', `translate(0, ${svgHeight - svgMargin})`)
    .selectAll('text')
    .style('transform', 'translate(-12px, 0) rotate(-50deg)')
    .style('text-anchor', 'end')
    .style('cursor', 'pointer')
    .style('font', '10px verdana')

  const twitterLine = d3.line()
    .x(d => xScale(d.year))
    .y(d => yScale(d.followers.twitter));

  lineGraph.append('path')
    .attr('d', twitterLine(data))
    .attr('stroke', twitterColor)
    .attr('stroke-width', 3)
    .attr('fill', 'transparent');

  const tumblrLine = d3.line()
    .x(d => xScale(d.year))
    .y(d => yScale(d.followers.tumblr));

  lineGraph.append('path')
    .attr('d', tumblrLine(data))
    .attr('stroke', tumblrColor)
    .attr('stroke-width', 3)
    .attr('fill', 'transparent');

  const instagramLine = d3.line()
    .x(d => xScale(d.year))
    .y(d => yScale(d.followers.instagram));

  lineGraph.append('path')
    .attr('d', instagramLine(data))
    .attr('stroke', instagramColor)
    .attr('stroke-width', 3)
    .attr('fill', 'transparent');
    
  lineGraph.selectAll('twitter-circles')
    .data(data)



</script> 

--solutions--

<script>
  const data = [ 
    { year: 2012, followers: { twitter: 2594, tumblr:  401, instagram:   83 }},
    { year: 2013, followers: { twitter: 3049, tumblr:  440, instagram:  192 }},
    { year: 2014, followers: { twitter: 3511, tumblr:  415, instagram:  511 }},
    { year: 2015, followers: { twitter: 3619, tumblr:  492, instagram: 1014 }},
    { year: 2016, followers: { twitter: 4046, tumblr:  543, instagram: 2066 }},
    { year: 2017, followers: { twitter: 3991, tumblr:  701, instagram: 3032 }},
    { year: 2018, followers: { twitter: 3512, tumblr: 1522, instagram: 4512 }},
    { year: 2019, followers: { twitter: 3274, tumblr: 1989, instagram: 4715 }},
    { year: 2020, followers: { twitter: 2845, tumblr: 2040, instagram: 4801 }}
  ];
</script>
<script>
  const svgMargin = 70,
    svgWidth = 700,
    svgHeight = 500,
    twitterColor = '#7cd9d1',
    tumblrColor = '#f6dd71',
    instagramColor = '#fd9b98';

  const lineGraph = d3.select('.dashboard')
    .append('svg')
    .attr('width', svgWidth)
    .attr('height', svgHeight);

  const yScale = d3.scaleLinear()
    .domain([0, 5000])
    .range([svgHeight - svgMargin, svgMargin]);

  const xScale = d3.scaleLinear()
    .domain([2012, 2020])
    .range([svgMargin, svgWidth - svgMargin]);

  const yAxis = d3.axisLeft(yScale)
    .ticks(6, '~s');

  const xAxis = d3.axisBottom(xScale)
    .tickFormat(d3.format(''))
    .tickPadding(10);

  lineGraph.append('g')
    .call(yAxis)
    .attr('transform', `translate(${svgMargin}, 0)`)
    .style('font', '10px verdana');

  lineGraph.append('g')
    .call(xAxis)
    .attr('transform', `translate(0, ${svgHeight - svgMargin})`)
    .selectAll('text')
    .style('transform', 'translate(-12px, 0) rotate(-50deg)')
    .style('text-anchor', 'end')
    .style('cursor', 'pointer')
    .style('font', '10px verdana')

  const twitterLine = d3.line()
    .x(d => xScale(d.year))
    .y(d => yScale(d.followers.twitter));

  lineGraph.append('path')
    .attr('d', twitterLine(data))
    .attr('stroke', twitterColor)
    .attr('stroke-width', 3)
    .attr('fill', 'transparent');

  const tumblrLine = d3.line()
    .x(d => xScale(d.year))
    .y(d => yScale(d.followers.tumblr));

  lineGraph.append('path')
    .attr('d', tumblrLine(data))
    .attr('stroke', tumblrColor)
    .attr('stroke-width', 3)
    .attr('fill', 'transparent');

  const instagramLine = d3.line()
    .x(d => xScale(d.year))
    .y(d => yScale(d.followers.instagram));

  lineGraph.append('path')
    .attr('d', instagramLine(data))
    .attr('stroke', instagramColor)
    .attr('stroke-width', 3)
    .attr('fill', 'transparent');
    
  lineGraph.selectAll('twitter-circles')  
    .data(data)
    .enter()

  

</script>