freeCodeCamp/add-a-hover-effect-to-a-d3-element.english.md at a658af6d184eefe0256a7ff2b4b34cbf27aa345f

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Daniel Simeonov 81d7127a5d Added solution for English/Data-Visualization/Hover-tod3-element (#36220 )

* Added solution for English/Data-Visualization/Hover-tod3-element

* Added full solution for Data-Visualization-D3/Hover-effect-to-d3-element

* fix: added extra line to prevent linting errors

2019-06-20 09:49:47 -07:00

2.9 KiB

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id, title, challengeType

id	title	challengeType
587d7faa367417b2b2512bd4	Add a Hover Effect to a D3 Element	6

Description

It's possible to add effects that highlight a bar when the user hovers over it with the mouse. So far, the styling for the rectangles is applied with the built-in D3 and SVG methods, but you can use CSS as well. You set the CSS class on the SVG elements with the attr() method. Then the :hover pseudo-class for your new class holds the style rules for any hover effects.

Instructions

Use the attr() method to add a class of bar to all the rect elements. This changes the fill color of the bar to brown when you mouse over it.

Tests

tests:
  - text: Your <code>rect</code> elements should have a class of <code>bar</code>.
    testString: assert($('rect').attr('class') == "bar", 'Your <code>rect</code> elements should have a class of <code>bar</code>.');

Challenge Seed

<style>
  .bar:hover {
    fill: brown;
  }
</style>
<body>
  <script>
    const dataset = [12, 31, 22, 17, 25, 18, 29, 14, 9];

    const w = 500;
    const h = 100;

    const svg = d3.select("body")
                  .append("svg")
                  .attr("width", w)
                  .attr("height", h);

    svg.selectAll("rect")
       .data(dataset)
       .enter()
       .append("rect")
       .attr("x", (d, i) => i * 30)
       .attr("y", (d, i) => h - 3 * d)
       .attr("width", 25)
       .attr("height", (d, i) => 3 * d)
       .attr("fill", "navy")
       // Add your code below this line



       // Add your code above this line

    svg.selectAll("text")
       .data(dataset)
       .enter()
       .append("text")
       .text((d) => d)
       .attr("x", (d, i) => i * 30)
       .attr("y", (d, i) => h - (3 * d) - 3);

  </script>
</body>

Solution

<style>
  .bar:hover {
    fill: brown;
  }
</style>
<body>
  <script>
    const dataset = [12, 31, 22, 17, 25, 18, 29, 14, 9];

    const w = 500;
    const h = 100;

    const svg = d3.select("body")
                  .append("svg")
                  .attr("width", w)
                  .attr("height", h);

    svg.selectAll("rect")
       .data(dataset)
       .enter()
       .append("rect")
       .attr("x", (d, i) => i * 30)
       .attr("y", (d, i) => h - 3 * d)
       .attr("width", 25)
       .attr("height", (d, i) => 3 * d)
       .attr("fill", "navy")
       // Add your code below this line
       .attr('class', 'bar')
       // Add your code above this line

    svg.selectAll("text")
       .data(dataset)
       .enter()
       .append("text")
       .text((d) => d)
       .attr("x", (d, i) => i * 30)
       .attr("y", (d, i) => h - (3 * d) - 3);
  </script>
</body>

2.9 KiB Raw Blame History