example-1-4.js

//size the visible area of the graph using the margin values
var width = 500, height = 500;

var margin = {top: 30, right: 10, bottom: 40, left: 60},
    width = width - margin.left - margin.right,
    height = height - margin.top - margin.bottom;

var minDate = (data[0].date),
    maxDate = data[data.length-1].date;
    minObjectValue = getMinObjectValue(data, 'DAU');
    maxObjectValue = getMaxObjectValue(data, 'DAU');

//create the graph object
var vis= d3.select("#metrics").append("svg")
    .data(data)
    .attr("class", "metrics-container")
    .attr("width", width + margin.left + margin.right)
    .attr("height", height + margin.top + margin.bottom)
    .append("g")
    .attr("transform", "translate(" + margin.left + "," + margin.top + ")");

var y = d3.scale.linear()
    .domain([ minObjectValue - (.1 * minObjectValue) , maxObjectValue + (.1 * maxObjectValue)])
    .range([height, 0]),
x = d3.time.scale()
    .domain([minDate, maxDate])
    .range([0, width]);