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--description--

By default, scales use the identity relationship. This means the input value maps to the output value. However, scales can be much more flexible and interesting.

Say a dataset has values ranging from 50 to 480. This is the input information for a scale, also known as the domain.

You want to map those points along the x axis on the SVG, between 10 units and 500 units. This is the output information, also known as the range.

The domain() and range() methods set these values for the scale. Both methods take an array of at least two elements as an argument. Here's an example:

scale.domain([50, 480]);
scale.range([10, 500]);
scale(50)
scale(480)
scale(325)
scale(750)
d3.scaleLinear()

In order, the following values would be displayed in the console: 10, 500, 323.37, and 807.67.

Notice that the scale uses the linear relationship between the domain and range values to figure out what the output should be for a given number. The minimum value in the domain (50) maps to the minimum value (10) in the range.

--instructions--

Create a scale and set its domain to [250, 500] and range to [10, 150].

Note: You can chain the domain() and range() methods onto the scale variable.

--hints--

Your code should use the domain() method.

assert(code.match(/\.domain/g));

The domain() of the scale should be set to [250, 500].

assert(JSON.stringify(scale.domain()) == JSON.stringify([250, 500]));

Your code should use the range() method.

assert(code.match(/\.range/g));

The range() of the scale should be set to [10, 150].

assert(JSON.stringify(scale.range()) == JSON.stringify([10, 150]));

The text in the h2 should be -102.

assert($('h2').text() == '-102');

--seed--

--seed-contents--​

<body>
  <script>
    // Add your code below this line
    const scale = d3.scaleLinear();



    // Add your code above this line
    const output = scale(50);
    d3.select("body")
      .append("h2")
      .text(output);
  </script>
</body>

--solutions--

<body>
  <script>
    const scale = d3.scaleLinear();
    scale.domain([250, 500])
    scale.range([10, 150])
    const output = scale(50);
    d3.select("body")
      .append("h2")
      .text(output);
  </script>
</body>