Formatting bar graph for integers developed using d3.js - d3.js

Question

I have developed bar graph using d3.js. The developed bar graph is included in fiddle. I am new to d3.js .So I am in difficulty for formatting graph. I desire to format graph more than the graph shown below.
The main problem I have experienced is ,the graph do not show -ve integer next to the -ve to be plotted in the y axis. ex) The value plotted is -490 , my current graph do not show -500 in y -axis. This issue is also exiting +ve values
The code is given below
var mainApp = angular.module('mainApp', []);
mainApp.controller('FIItradingController',
['$scope', function($scope) {
var data = [
{name: "01-12-2014", value: 4984.6},
{name: "02-12-2014", value: -109.45},
{name: "03-12-2014", value: 474},
{name: "04-12-2014", value: 391.07},
{name: "05-12-2014", value: 106.82},
{name: "06-12-2014", value: -12.36},
{name: "07-12-2014", value: 10},
{name: "08-12-2014", value: 20}
];
var data1 = [4, 8, 15, 16, 23, 42];
var margin = {top: 20, right: 30, bottom: 30, left: 40},
width = 960 - margin.left - margin.right,
height = 500 - margin.top - margin.bottom;
var x = d3.scale.ordinal()
.rangeRoundBands([0, width], .1);
var y = d3.scale.linear()
.range([height, 0]);
var xAxis = d3.svg.axis()
.scale(x)
.orient("bottom");
var yAxis = d3.svg.axis()
.scale(y)
.orient("left");
/*var x = d3.scale.linear()
.range([0, width]);*/
/*var chart = d3.select(".chart")
.attr("width", width);*/
/*var x = d3.scale.linear()
.domain([0, d3.max(data)])
.range([0, width]);*/
var chart = d3.select(".chart")
.attr("width", width + margin.left + margin.right)
.attr("height", height + margin.top + margin.bottom)
.append("g")
.attr("transform", "translate(" + margin.left + "," + margin.top + ")");
$scope.render = function(data) {
/*var chart = d3.select(".chart")
.attr("width", width)
.attr("height", barHeight * data.length);*/
/*bar.append("rect")
.attr("width", x)
.attr("height", barHeight - 1);
bar.append("rect")
.attr("width", function(d) { return x(d.value); })
.attr("height", barHeight - 1);
bar.append("text")
.attr("x", function(d) { return x(d.value) - 3; })
.attr("y", barHeight / 2)
.attr("dy", ".35em")
.text(function(d) { return d.value; });
x.domain([0, d3.max(data, function(d) { return d.value; })]);
chart.attr("height", barHeight * data.length);
*/
x.domain(data.map(function(d) { return d.name; }));
//y.domain([0, d3.max(data, function(d) { return d.value; })]);
y.domain([d3.min(data,function(d){return d.value}), d3.max(data, function(d) { return d.value; })]);
chart.append("g")
.attr("class", "x axis")
.attr("transform", "translate(0," + (height) + ")")
.call(xAxis);
chart.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("Frequency");
/*chart.selectAll(".bar")
.data(data)
.enter().append("rect")
.attr("class", "bar")
.attr("x", function(d) { return x(d.name); })
.attr("y", function(d) { return y(d.value); })
.attr("height", function(d) { return height - y(d.value); })
.attr("width", x.rangeBand());*/
chart.selectAll(".bar")
.data(data)
.enter().append("rect")
.attr("class", function(d) { return d.value < 0 ? "bar negative" : "bar positive"; })
.attr("y", function(d) {return y(Math.max(0, d.value)); })
.attr("x", function(d) { return x(d.name); })
.attr("height", function(d) {return Math.abs(y(d.value) - y(0)); })
.attr("width", x.rangeBand());
}
function type(d) {
d.value = +d.value; // coerce to number
return d;
}
$scope.render(data);
}]);
If any one know please help me. The fiddle is given below
http://jsfiddle.net/HB7LU/8960/

Answer 1

So, your plot is showing the negative value—it's just that it looks like it drops off below the chart area because the lowest point on the y-axis is where your chart ends.
There are a several ways you get around this (like multiplying the output of d3.min() by 1.1 to give a little extra room), but probably the easiest and most elegant is just to add .nice() to your y-scale, like so:
y.domain([d3.min(data,function(d){return d.value}), d3.max(data, function(d) { return d.value; })])
.nice();
You might also consider using d3.extent() instead of d3.min() and d3.max(). It returns a two-value array of the minimum and maximum values in an array. And I'd also put chain .domain() and .nice() onto y right after its definition; nothing necessitates it being declared 40 lines later. Now we have this:
var y = d3.scale.linear()
.range([height, 0])
.domain(d3.extent(data, function(d) { return d.value; }))
.nice();
Forked fiddle.