d3.min.js gives Uncaught TypeError: n.apply is not a function - date

Question

I'm trying to split a datetime in two variables cx (should be the day in the year) and cy (should be the hour+minute/60) according to:
<!-- date format of d.date: 24-8-2016 9:47:38-->
var parseDayinYearFormat = d3.time.format('%j').parse;
var parseHourFormat = d3.time.format('%H').parse;
var parseMinuteFormat = d3.time.format('%M').parse;
<!-- add the objects-->
var circles = svg.selectAll("circle")
.data(data)
.enter()
.append("circle");
var circleAttributes = circles
.attr("cx", function (d) { return +parseDayinYearFormat(d.date); })
.attr("cy", function (d) { return +parseHourFormat(d.date)+(parseMinuteFormat(d.date)/60); })
.attr("r", function (d) { return 20.0/(9-d.total); })
.attr("class", function (d) {if (d.w>d.total-d.w) {return "cr"} else { return "cb" }});
But d3 isn't playing nice: cx and cy become a NaN and d3 is giving the error Uncaught TypeError: n.apply is not a function
Please help.

Answer 1

You need to parse the entire string with a single format object. You can’t parse the string with a sequence of parsings.
Using the d3 version 3.x documentation I came up with the following, which works on your example.
var datestring = '24-8-2016 9:47:38';
var format = d3.time.format('%-d-%-m-%Y %-H:%-M:%-S');
console.log(format.parse(datestring))
// "2016-08-24T13:47:38.000Z" // (my time zone is UTC-4)
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.4.11/d3.min.js"></script>
Note that because your example 24-8-2016 9:47:38 has many fields that show no zero-padding, I use a dash between the % and the specifier, i.e., %-d, to tell d3 that there may be no zero in the beginning.
Also note that in your example, there is no way 24 is a day-of-year, which is between 1 and 366: 24 is clearly just a day of the month, right?
However, it appears from your code snippet that you just want to extract the day and hour and minute from a string. For this simple purpose, d3.time.format might be overkill, since it gives you a Date object, which then you have to parse to extract the day/hour/minute. Consider using a regular expression for this task.