Introduction

I never set out to write treatise on D3… But here I am three years after publishing the first version of this book and I’m in the process of updating it for version 4 of d3.js, while also looking back at a range of other books that have been written as a result of this first foray into publishing.

I am a simple user of this extraordinary framework and when I say simple, I really mean I had no idea how to get it to do anything when I started; I needed to do a lot of searching and learned by trial-and-error (emphasis on the errors which were entirely mine). The one thing that I did know was that the example graphics shown by Mike Bostock and others were the sort of graphical goodness that I wanted to play with.

So to get from the point of having no skills whatsoever to the point where I could begin to code up something to display data in a way I wanted, I had to capture the information as I went. The really cool thing about this sort of process is that it doesn’t need to occur all at once. You can start with no knowledge whatsoever (or pretty close) and by standing on the shoulders of other’s work, you can add building blocks to improve what you’re seeing and then change the blocks to adapt and improve.

For example (and this is pretty much how it started). I wanted to draw a line graph, so I imported an example and then got it running locally on my computer. Then I worked out how to change the example data for my data. Then I worked out how to move the Y axis from the right to the left. Then how to make the axis labels larger, change the tick size, make the lines fatter, change the colour, add a label, fill the area under the graph, put the graph in the centre of the page, add a glow to the text to help it stand out, put it in a framework (bootstrap), add buttons to change data sets, animate the transitions between data sets, update the data automatically when it changed, add a pan and zoom feature, turn parts of the graph into hyperlinks to move to other graphs… And then I started on bar graphs :-).

The point to take away from all of this is that any one graph is just a collection of lots of blocks of code, each block designed to carry out a specific function. Pick the blocks you want and implement them.

I found it was much simpler to work on one thing (block) at a time, and this helped greatly to reduce the uncertainty factor when things didn’t work as anticipated. I’m not going to pretend that everything I’ve done while trying to build graphs employs the most elegant or efficient mechanism, but in the end, if it all works on the screen, I walk away happy :-). That’s not to say I have deliberately ignored any best practices – I just never knew what they were. Likewise, wherever possible, I have tried to make things as extensible as possible.

D3 has also steered down the road of providing standalone micro-libraries available as components and this flexibility continues to redefine the maxim of change being the only constant in the software world.

You will find that I have typically eschewed a simple “Do this approach” for more of a story telling exercise. This means that some explanations are longer and more flowery than might be to everyone’s liking, but there you go, try to be brave :-)

I’m sure most authors try to be as accessible as possible. I’d like to do the same, but be warned… There’s a good chance that if you ask me a technical question I may not know the answer. So please be gentle with your emails :-).

Email: ‘d3noobmail+contact@gmail.com’