Add space between x-axis and line with time scale

Question

I am using an example below.

HTML-

<div id="chart-holder"></div>

CSS-

.chart-holder {
   position: relative;
   font-family: Helvetica, sans-serif;
}

.chart-tip {
   display: none;
   position: absolute;
   min-width: 70px;
   top: 0px;
   left: 0px;
   padding: 3px 5px;
   background: rgba(0, 0, 0, 0.8);
   color: #fff;
   font-size: .8em;
   text-shadow: none;
   text-align: center;
   z-index: 10500;
   border-radius: 3px;
}

.v {
   display: block;
   font-size: 1.2em;
 }

path {
   stroke: #0da9c0;
   stroke-width: 2;
   fill: none;
}

path.domain {
   stroke: #aaa;
   stroke-width: 1;
}

line {
   stroke: #aaa;
}

text {
    font-family: Arial;
    font-size: 9pt;
    fill: #555;
}

circle {
   cursor: pointer;
}

Javascript-

var data     = [["2013-01-24 06:38:02.235191", 52], ["2013-01-23 06:38:02.235310", 54], ["2013-01-22 06:38:02.235330", 45], ["2013-01-21 06:38:02.235346", 53]],
  maxValue = d3.max(data, function (d) { return d[1]; }),
  margin   = {top: 20, right: 20, bottom: 50, left: 50},
  width    = 500 - margin.left - margin.right,
  height   = 300 - margin.top - margin.bottom,
  svg, x, y, xAxis, yAxis, line;

$.each(data, function(index, val) {
    val[0] = new Date(val[0]);
  });

x = d3.time.scale()
  .range([0, width])

y = d3.scale.linear()
  .domain([0, maxValue])
  .range([height, 0]);

xAxis = d3.svg.axis()
  .scale(x)
  .tickSize(4, 2, 0)
  .ticks(d3.time.days, 1)
  .tickFormat(d3.time.format("%m/%d"))
  .orient("bottom");

yAxis = d3.svg.axis()
  .scale(y)
  // .ticks(5)
  // .tickValues([0, maxValue * 0.25, maxValue * 0.5, maxValue * 0.75, maxValue])
  .tickSize(4, 2, 0)
  .orient("left");

line = d3.svg.line()
  .x(function(d) { return x(d[0]); })
  .y(function(d) { return y(d[1]); });

svg = d3.select("#chart-holder").append("svg")
  .attr("width", width + margin.left + margin.right)
  .attr("height", height + margin.top + margin.bottom)
.append("g")
  .attr("transform", "translate(" + margin.left + "," + margin.top + ")");

x.domain(d3.extent(data, function(d) { return d[0]; }));
y.domain([d3.min(data, function (d) { return d[1]; })-1, maxValue]);

svg.append("g")
  .attr("class", "x axis")
  .attr("transform", "translate(0," + height + ")")
  .call(xAxis)
  .selectAll("text")
    .attr("transform", function(d) {
      return "rotate(-60)translate(" + -this.getBBox().height * 1.7 + "," +
        -this.getBBox().width/4 + ")";
    });

svg.append("g")
  .attr("class", "y axis")
  .call(yAxis);
// .append("text")
//   .attr("transform", "rotate(-90)")
//   .attr("y", 6)
//   .attr("dy", ".71em")
//   .style("text-anchor", "end")
//   .text("Engagement");

svg.append("path")
  .datum(data)
  .attr("class", "line")
  .attr("d", line);

svg
 .selectAll("circle")
 .data(data)
 .enter().append("circle")
 .attr("fill", "#0b8da0")
 .attr("r", 3.5)
 .attr("cx", function(d) { return x(d[0]); })
 .attr("cy", function(d) { return y(d[1]); })
 .on("mouseover", function(d) { showData(this, d);})
 .on("mouseout", function() { hideData(this);});

 function showData(obj, d) {
  var coord = d3.mouse(obj);
  var chartTip = d3.select(".chart-tip");
  var format = d3.time.format("%b %d, %Y");

  // enlarge circle
  d3.select(obj)
  .attr('r', 5);

  // now we just position the chartTip roughly where our mouse is
  chartTip.style("left", (coord[0] + 60) + "px" );
  chartTip.style("top", (coord[1] + 10) + "px");
  $(".chart-tip").html('<span class="v">' + d[1] + '</span>' + format(d[0]));
  $(".chart-tip").fadeIn(100);
}

function hideData(obj) {
  // enlarge circle
  d3.select(obj)
  .attr('r', 3.5);
  $(".chart-tip").fadeOut(100);
}

$('#chart-holder').append($('<div />', {
  'class': 'chart-tip'
}));

Here is the fiddle

http://jsfiddle.net/murli2308/n7Vmr/12/

I can add space between axis and line if I am using ordinal scale or linear scale. But when I am using time scale, I am not able to add space between axis and line.

I tried

 x = d3.time.scale()
  .range([0, width]);

It is not working.

Answer 1

The x.domain is the user space side of the user space to pixel space mapping. In your code you are setting the domain as:

x.domain(d3.extent(data, function(d) { return d[0] - 1; }));

Which says start my x axis at my min time minus 1 millisecond.

If you want some space before / after the line. Try:

x.domain([
  d3.min(data, function(d) { return d[0].getTime() - 1.8e+7; }),
  d3.max(data, function(d) { return d[0].getTime() + 1.8e+7; })
]);

Which says start my x axis 5 hours before my min date and stop it 5 hours after my max date.

Updated fiddle.

EDITS

Just used a percentage based scheme, say you want 5% padding (3.6 hours with your current data):

var minDate = d3.min(data, function(d) { return d[0].getTime(); }),
    maxDate = d3.max(data, function(d) { return d[0].getTime(); }),
    padding = (maxDate - minDate) * .05;

x.domain([minDate - padding, maxDate + padding]);

Updated fiddle.