Customize the d3 month or year tick format

Question

So I made a chart in d3 and used the default x axis format,

d3.axisBottom(x)

which output the following graph:

How can I manually create and customize this format? In particular, I'd like to use short month names, like "Oct", so that "October" doesn't obscure the following year label.

Answer 1

Use tickFormat to format the ticks in your x axis. In your case, .tickFormat(d3.timeFormat("%b")) will return short month names (but it will make the year disappear).

Here is the demo:

var svg = d3.select("body")
  .append("svg")
  .attr("width", 500)
  .attr("height", 100)   
            
var xScale = d3.scaleTime()
  .domain([new Date("2014-01-01"), new Date("2016-01-01")])
  .range([0, 450]);
        
var xAxis = d3.axisBottom(xScale)
  .tickFormat(d3.timeFormat("%b"));
  
svg.append("g")
  .call(xAxis);

<script src="https://d3js.org/d3.v4.min.js"></script>

To keep the month / year default functionality, you need to create your own custom format.

var xAxis = d3.axisBottom(xScale)
   .tickFormat(function(date){
       if (d3.timeYear(date) < date) {
         return d3.timeFormat('%b')(date);
       } else {
         return d3.timeFormat('%Y')(date);
       }
    });

Check the demo:

var svg = d3.select("body")
  .append("svg")
  .attr("width", 500)
  .attr("height", 100)   
            
var xScale = d3.scaleTime()
  .domain([new Date("2014-01-01"), new Date("2016-01-01")])
  .range([0, 500]);

var xAxis = d3.axisBottom(xScale)
  .tickFormat(function(date){
    if (d3.timeYear(date) < date) {
      return d3.timeFormat('%b')(date);
    } else {
      return d3.timeFormat('%Y')(date);
    }
  });
  
svg.append("g")
  .attr("class", "x axis")
  .call(xAxis);
	
d3.selectAll(".ticks");

<script src="https://d3js.org/d3.v4.min.js"></script>