pland pland - 3 months ago 40
Jade Question

How to use D3 in Node.js properly?

I've been trying to invoke D3 within Node.js. I tried firstly to import d3.v2.js from D3's website with the script tag, but then read this thread:

Wanna run d3 from a Cakefile

Where D3's author advises one should 'npm install d3'...I did this, and I can successfully invoke it in node console:

dpc@ananda:$ node
> var d3 = require("d3");
undefined
> d3.version;
'2.8.1'


However, when trying to invoke it from app.js with 'node app.js', I get:

node.js:201
throw e; // process.nextTick error, or 'error' event on first tick
^
TypeError: Cannot read property 'BSON' of undefined
at /Users/dpc/Dropbox/sync/Business/MindfulSound/Development/nad.am/nadam/node_modules/mongoose/node_modules/mongodb/lib/mongodb/index.js:45:44


I realise that elsewhere, D3's author has clearly specified that one should require the canvas:

https://github.com/mbostock/d3/blob/master/examples/node-canvas/us-counties.js

as:

var Canvas = require("canvas");


but even then, (and even if specifically requiring index.js instead of d3.v2.js in a require statement in app.js), I can't get the below to work within a Jade template:

- script('/javascripts/d3.v2.js')
h1 Dashboard
section.css-table
section.two-column
section.cell
hr.grey
h2 Statistics
#mainGraph
script(type="text/javascript")
var Canvas = require("canvas");
var w = 400,
h = 400,
r = Math.min(w, h) / 2,
data = d3.range(10).map(Math.random).sort(d3.descending),
color = d3.scale.category20(),
arc = d3.svg.arc().outerRadius(r),
donut = d3.layout.pie();
var vis = d3.select("body").append("svg")
.data([data])
.attr("width", w)
.attr("height", h);
var arcs = vis.selectAll("g.arc")
.data(donut)
.enter().append("g")
.attr("class", "arc")
.attr("transform", "translate(" + r + "," + r + ")");
var paths = arcs.append("path")
.attr("fill", function(d, i) { return color(i); });
paths.transition()
.ease("bounce")
.duration(2000)
.attrTween("d", tweenPie);
paths.transition()
.ease("elastic")
.delay(function(d, i) { return 2000 + i * 50; })
.duration(750)
.attrTween("d", tweenDonut);

function tweenPie(b) {
b.innerRadius = 0;
var i = d3.interpolate({startAngle: 0, endAngle: 0}, b);
return function(t) {
return arc(i(t));
};
}

function tweenDonut(b) {
b.innerRadius = r * .6;
var i = d3.interpolate({innerRadius: 0}, b);
return function(t) {
return arc(i(t));
};

section.cell
hr.grey
h2 Achievements

Answer

The correct way to use D3 within Node is to use NPM to install d3 and then to require it. You can either npm install d3 or use a package.json file, followed by npm install:

{
  "name": "my-awesome-package",
  "version": "0.0.1",
  "dependencies": {
    "d3": "3"
  }
}

Once you have d3 in your node_modules directory, load it via require:

var d3 = require("d3");

And that's it.

Regarding your other issues: Canvas is not required to use D3. The node-canvas example you linked requires canvas because it renders to a canvas. The TypeError (Cannot read property 'BSON' of undefined) appears to be related to your use of mongoose / monogdb, not D3.