D3 function to parse the date not working

Question

I have a d3 visualisation that works fine with the current stable release (3.x) however I wanted to implement the Pan & Zoom function so I upgraded to 4.alpha.

This threw a lot of bugs as the syntax has changed. I updated the variable names, however there is one remaining bug pertaining to the second line of the following code:

function type(d) {
   d.date = formatDate.parse(d.date);
   d.Flux = +d.Flux;
   return d;
}

Opening up the page source via the browser, I see that formatDate.parse is not a function. The visualisation is currently not rendering.

I have tried combing the D3 4.alpha documentation, to no avail.

Further up in the code, formatDate is defined as follows:

var formatDate = d3.timeFormat("%d-%b-%y");

I am happy to post the original code, its about 70 lines long, and a bit hacky tho:

---

var margin = {top: 20, right: 20, bottom: 30, left: 50},
    width = 1400// - margin.left - margin.right,
    height = 1400// - margin.top - margin.bottom;
var formatDate = d3.timeFormat("%d-%b-%y");
var x = d3.scaleLinear()
    .range([0, width]);
var y = d3.scaleLinear()
    .range([height, 0]);
var line = d3.line()
    .x(function(d) { return x(d.date); })
    .y(function(d) { return y(d.Flux); });
var svg = d3.selectAll("#ExoPlanet, #ExoPlanet2").append("svg")
    .attr("width", '90%')
    .attr("height", '70%')
    .attr('viewBox','0 0 '+Math.min(width,height)+' '+Math.min(width,height))
    .attr('preserveAspectRatio','xMinYMin')
    .append("g")
    .call(d3.zoom()
        .scaleExtent([1 / 2, 4])
        .on("zoom", zoomed)) ;
function zoomed() {
  var transform = d3.event.transform;
  circle.attr("transform", function(d) {
    return "translate(" + transform.applyX(d[0]) + "," + transform.applyY(d[1]) + ")";
  });
}

d3.tsv("/FluxTime.tsv", type, function(error, data) {
  if (error) throw error;
  x.domain(d3.extent(data, function(d) { return d.date; }));
  y.domain(d3.extent(data, function(d) { return d.Flux; }));
    svg.selectAll("dot")
        .data(data)
      .enter().append("circle")
        .attr("r", 2.0)
        .attr("cx", function(d) { return x(d.date); })
        .attr("cy", function(d) { return y(d.Flux); })
        .attr("stroke", "#CE9A76");
});
function type(d) {
  d.date = formatDate.parse(d.date));
  d.Flux = +d.Flux;
  return d;

}

A screenshot of the first 8 entries in the dataset:

Answer 1

In D3 3.5, you could parse just the way you did, setting the time format...

var formatDate = d3.time.format("%d-%b-%y");

...and then using this time format to parse:

d.date = formatDate.parse(d.date);

But, using D3 4.0, you have to parse dates in a different way, using timeParse:

var parseTime = d3.timeParse("%d-%b-%y");

And, then, modifying your accessor function:

function type(d) {
  d.date = parseTime(d.date);
  d.Flux = +d.Flux;
  return d;
}