curriculum/challenges/english/blocks/data-visualization-with-d3/587d7fa8367417b2b2512bcc.md
The last challenge created an svg element with a given width and height, which was visible because it had a background-color applied to it in the style tag. The code made space for the given width and height.
The next step is to create a shape to put in the svg area. There are a number of supported shapes in SVG, such as rectangles and circles. They are used to display data. For example, a rectangle (<rect>) SVG shape could create a bar in a bar chart.
When you place a shape into the svg area, you can specify where it goes with x and y coordinates. The origin point of (0, 0) is in the upper-left corner. Positive values for x push the shape to the right, and positive values for y push the shape down from the origin point.
To place a shape in the middle of the 500 (width) x 100 (height) svg from last challenge, the x coordinate would be 250 and the y coordinate would be 50.
An SVG rect has four attributes. There are the x and y coordinates for where it is placed in the svg area. It also has a height and width to specify the size.
Add a rect shape to the svg using append(), and give it a width attribute of 25 and height attribute of 100. Also, give the rect x and y attributes each set to 0.
Your document should have 1 rect element.
assert.lengthOf(document.querySelectorAll('rect'), 1);
The rect element should have a width attribute set to 25.
assert.strictEqual(document.querySelector('rect')?.getAttribute('width'), '25');
The rect element should have a height attribute set to 100.
assert.strictEqual(
document.querySelector('rect')?.getAttribute('height'),
'100'
);
The rect element should have an x attribute set to 0.
assert.strictEqual(document.querySelector('rect')?.getAttribute('x'), '0');
The rect element should have a y attribute set to 0.
assert.strictEqual(document.querySelector('rect')?.getAttribute('y'), '0');
<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);
// Add your code below this line
// Add your code above this line
</script>
</body>
<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)
.append('rect')
.attr('width', 25)
.attr('height', 100)
.attr('x', 0)
.attr('y', 0);
</script>
</body>