D3 v4 .rangeBand() equivalent

Question

In D3 version 4.x, d3.scale.ordinal() has been changed to d3.scaleOrdinal and d3.rangeRoundBands has been changed to:

d3.scaleBand()
  .rangeRound([range]);

To find the width of a band, what is the equivalent of d3.rangeBand()?

Answer 1

To find the width of the band in a band scale you have to use:

scale.bandwidth();

According to the API, bandwidth():

Returns the width of each band.

Here is a demo:

var scale = d3.scaleBand()
  .domain(["foo", "bar", "baz", "foobar", "foobaz"])
  .range([0, 100]);
  
console.log("The width of each band is " + scale.bandwidth() + " pixels")

<script src="https://d3js.org/d3.v5.min.js"></script>

As you can see, the bandwidth depends on the number of elements in the domain, the extent of the range and the paddings. Here is the same snippet above, with paddings:

var scale = d3.scaleBand()
  .domain(["foo", "bar", "baz", "foobar", "foobaz"])
  .range([0, 100])
  .paddingOuter(0.25)
  
console.log("The width of each band is " + scale.bandwidth() + " pixels")

<script src="https://d3js.org/d3.v5.min.js"></script>