index.js

var _ = require('lodash');
var d3 = require('d3');

function randomVariable(rate) {
  rate = rate || 1;
  var U = Math.random();
  return -Math.log(U)/rate;
};

var start = 0;
var end = 25;
var step = 0.01;
var eventsPerStep = 5;

var generateData = function () {
  var data = [];
  _.each(_.range(start, end, step), function(i) {
    _.each(_.range(Math.random() * eventsPerStep), function() {
      data.push({
        x1: i,
        x2: i + randomVariable()
      });
    });
  });
  return data;
}
var data = generateData();

var width = 800;
var height = 600;

var x = d3.scale.linear().domain([start, end]).range([0, width]);
// var y = d3.scale.linear().domain([start, end]).range([0, width]);

var svg = d3.select('body').append('svg')
      .attr('width', width)
      .attr('height', height);


svg.selectAll('rect')
    .data(data)
   .enter()
   .append('rect')
      .attr('x', function(d, i) {
        return x(d.x1);
      })
      .attr('y', function(d, i) {
        return i;
      })
      .attr('width', function(d) {
        return x(d.x2) - x(d.x1);
      })
      .attr('height', 1)

package.json

{
  "name": "duration",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "chroma-js": "^1.1.1",
    "d3": "^3.5.16",
    "lodash": "^4.8.2"
  },
  "devDependencies": {
    "watchify": "^3.7.0"
  }
}