Tags: code



Tuesday, February 21st, 2017

kamranahmedse/design-patterns-for-humans: Design Patterns for Humans™ - An ultra-simplified explanation

I’m crap at object-oriented programming (probably because I don’t get get enough practice), but I’ve had a quick read through this and it looks like a nice clear primer. I shall return and peruse in more depth next time I’m trying to remember how to do all this class-based stuff.

Monday, February 20th, 2017


I really enjoyed teaching in Porto last week. It was like having a week-long series of CodeBar sessions.

Whenever I’m teaching at CodeBar, I like to be paired up with people who are just starting out. There’s something about explaining the web and HTML from first principles that I really like. And people often have lots and lots of questions that I enjoy answering (if I can). At CodeBar—and at The New Digital School—I found myself saying “Great question!” multiple times. The really great questions are the ones that I respond to with “I don’t know …let’s find out!”

CodeBar is always a very rewarding experience for me. It has given me the opportunity to try teaching. And having tried it, I can now safely say that I like it. It’s also a great chance to meet people from all walks of life. It gets me out of my bubble.

I can’t remember when I was first paired up with Amber at CodeBar. It must have been sometime last year. I do remember that she had lots of great questions—at some point I found myself explaining how hexadecimal colours work.

I was impressed with Amber’s eagerness to learn. I also liked that she was making her own website. I told her about Homebrew Website Club and she started coming along to that (along with other CodeBar people like Cassie and Alice).

I’ve mentioned to multiple CodeBar students that there’s pretty much an open-door policy at Clearleft when it comes to shadowing: feel free to come along and sit with a front-end developer while they’re working on client projects. A few people have taken up the offer and enjoyed observing myself or Charlotte at work. Amber was one of those people. Again, I was very impressed with her drive. She’s got a full-time job (with sometimes-crazy hours) but she’s so determined to get into the world of web design and development that she’s willing to spend her free time visiting Clearleft to soak up the atmosphere of a design studio.

We’ve decided to turn this into something more structured. Amber and I will get together for a couple of hours once a week. She’s given me a list of some of the areas she wants to explore, and I think it’s a fine-looking list:

  • I want to gather base, structural knowledge about the web and all related aspects. Things seem to float around in a big cloud at the moment.
  • I want to adhere to best practices.
  • I want to learn more about what direction I want to go in, find a niche.
  • I’d love to opportunity to chat with the brilliant people who work at Clearleft and gain a broad range of knowledge from them.

My plan right now is to take a two-track approach: one track about the theory, and another track about the practicalities. The practicalities will be HTML, CSS, JavaScript, and related technologies. The theory will be about understanding the history of the web and its strengths and weaknesses as a medium. And I want to make sure there’s plenty of UX, research, information architecture and content strategy covered too.

Seeing as we’ll only have a couple of hours every week, this won’t be quite like the masterclass I just finished up in Porto. Instead I imagine I’ll be laying some groundwork and then pointing to topics to research. I guess it’s a kind of homework. For example, after we talked today, I set Amber this little bit of research for the next time we meet: “What is the difference between the internet and the World Wide Web?”

I’m excited to see where this will lead. I find Amber’s drive and enthusiasm very inspiring. I also feel a certain weight of responsibility—I don’t want to enter into this lightly.

I’m not really sure what to call this though. Is it mentorship? Or is it coaching? Or training? All of the above?

Whatever it is, I’m looking forward to documenting the journey. Amber will be writing about it too. She is already demonstrating a way with words.

Wednesday, February 15th, 2017

CSS Beating Heart Tutorial. – Cassie Codes

A sweet CSS tutorial that Cassie put together for the Valentine’s Day Codebar.

Wednesday, February 8th, 2017

Polyfills and the evolution of the web - TAG finding

Really good advice for anyone thinking of releasing a polyfill into the world.

Tuesday, January 31st, 2017

Less Bro-gramming: Net Natives host and sponsor Codebar | Net Natives

An excellent potted history from Cassie on women in computing.

NASA’s “Keypunch girls” would work in cramped rows translating programming instructions onto paper pads, whilst the machine operators would sit in comfort, feeding the code decks through card readers and enjoying the esteem of the end result (I imagine it a bit like Mad Men, but with more sexism and astronauts).

Monday, January 30th, 2017

The Invention of Wireless Cryptography—The Appendix

A marvellous story of early twentieth century espionage over the airwaves.

In one proposal, hidden instructions were interspersed within regular, ordinary-looking messages by slightly lengthening the spaces between dots and dashes.

Sunday, January 29th, 2017

Callback Hell

At first when I was reading this JavaScript coding guide, I thought “Isn’t this exactly what promises address?” but that is then addressed further down:

Before looking at more advanced solutions, remember that callbacks are a fundamental part of JavaScript (since they are just functions) and you should learn how to read and write them before moving on to more advanced language features, since they all depend on an understanding of callbacks.

Fair enough. In any case, what you’ll find here is mainly good advice for writing modular code.

Life plus Linux: Look before you paste from a website to terminal

The (literally) hidden dangers of copying code snippets from the web and pasting them into the command line.

This cautionary tale backs up a small tip I heard for getting to understand how found code works: deliberately type it out instead of copying and pasting.

DirtyMarkup · Tidy up your HTML, CSS, and JavaScript code

A handy prettifier for front-end code. Useful if you’re trying to find something inside code markup, CSS, or JavaScript that’s been minified.

Saturday, January 28th, 2017

The Promise of a Burger Party - Mariko Kosaka

Mariko has a real knack for explaining technical concepts in a very accessible way. This time it’s JavaScript promises.

Thursday, January 19th, 2017

bastianallgeier/letter: Letter is a simple, highly customizable tool to create letters in your browser.

A nice little use of print (and screen) styles from Bastian—compose letters in a web browser.

Instead of messing around in Word, Pages or even Indesign, you can write your letters in the browser, export them as HTML or PDF (via Apple Preview).

Wednesday, January 11th, 2017

Making Resilient Web Design work offline

I’ve written before about taking an online book offline, documenting the process behind the web version of HTML5 For Web Designers. A book is quite a static thing so it’s safe to take a fairly aggressive offline-first approach. In fact, a static unchanging book is one of the few situations that AppCache works for. Of course a service worker is better, but until AppCache is removed from browsers (and until service worker is supported across the board), I’m using both. I wouldn’t recommend that for most sites though—for most sites, use a service worker to enhance it, and avoid AppCache like the plague.

For Resilient Web Design, I took a similar approach to HTML5 For Web Designers but I knew that there was a good chance that some of the content would be getting tweaked at least for a while. So while the approach is still cache-first, I decided to keep the cache fairly fresh.

Here’s my service worker. It starts with the usual stuff: when the service worker is installed, there’s a list of static assets to cache. In this case, that list is literally everything; all the HTML, CSS, JavaScript, and images for the whole site. Again, this is a pattern that works well for a book, but wouldn’t be right for other kinds of websites.

The real heavy lifting happens with the fetch event. This is where the logic sits for what the service worker should do everytime there’s a request for a resource. I’ve documented the logic with comments:

// Look in the cache first, fall back to the network
  // CACHE
  // Did we find the file in the cache?
      // If so, fetch a fresh copy from the network in the background
      // NETWORK
          // Stash the fresh copy in the cache
  // If the file wasn't in the cache, make a network request
      // Stash a fresh copy in the cache in the background
  // If the request is for an image, show an offline placeholder
  // If the request is for a page, show an offline message

So my order of preference is:

  1. Try the cache first,
  2. Try the network second,
  3. Fallback to a placeholder as a last resort.

Leaving aside that third part, regardless of whether the response is served straight from the cache or from the network, the cache gets a top-up. If the response is being served from the cache, there’s an additional network request made to get a fresh copy of the resource that was just served. This means that the user might be seeing a slightly stale version of a file, but they’ll get the fresher version next time round.

Again, I think this acceptable for a book where the tweaks and changes should be fairly minor, but I definitely wouldn’t want to do it on a more dynamic site where the freshness matters more.

Here’s what it usually likes like when a file is served up from the cache:

  .then( responseFromCache => {
  // Did we find the file in the cache?
  if (responseFromCache) {
      return responseFromCache;

I’ve introduced an extra step where the fresher version is fetched from the network. This is where the code can look a bit confusing: the network request is happening in the background after the cached file has already been returned, but the code appears before the return statement:

  .then( responseFromCache => {
  // Did we find the file in the cache?
  if (responseFromCache) {
      // If so, fetch a fresh copy from the network in the background
          // NETWORK
          .then( responseFromFetch => {
              // Stash the fresh copy in the cache
              .then( cache => {
                  cache.put(request, responseFromFetch);
      return responseFromCache;

It’s asynchronous, see? So even though all that network code appears before the return statement, it’s pretty much guaranteed to complete after the cache response has been returned. You can verify this by putting in some console.log statements:

.then( responseFromCache => {
  if (responseFromCache) {
          .then( responseFromFetch => {
              console.log('Got a response from the network.');
              .then( cache => {
                  cache.put(request, responseFromFetch);
      console.log('Got a response from the cache.');
      return responseFromCache;

Those log statements will appear in this order:

Got a response from the cache.
Got a response from the network.

That’s the opposite order in which they appear in the code. Everything inside the event.waitUntil part is asynchronous.

Here’s the catch: this kind of asynchronous waitUntil hasn’t landed in all the browsers yet. The code I’ve written will fail.

But never fear! Jake has written a polyfill. All I need to do is include that at the start of my serviceworker.js file and I’m good to go:

// Import Jake's polyfill for async waitUntil

I’m also using it when a file isn’t found in the cache, and is returned from the network instead. Here’s what the usual network code looks like:

  .then( responseFromFetch => {
    return responseFromFetch;

I want to also store that response in the cache, but I want to do it asynchronously—I don’t care how long it takes to put the file in the cache as long as the user gets the response straight away.

Technically, I’m not putting the response in the cache; I’m putting a copy of the response in the cache (it’s a stream, so I need to clone it if I want to do more than one thing with it).

  .then( responseFromFetch => {
    // Stash a fresh copy in the cache in the background
    let responseCopy = responseFromFetch.clone();
      .then( cache => {
          cache.put(request, responseCopy);
    return responseFromFetch;

That all seems to be working well in browsers that support service workers. For legacy browsers, like Mobile Safari, there’s the much blunter caveman logic of an AppCache manifest.

Here’s the JavaScript that decides whether a browser gets the service worker or the AppCache:

if ('serviceWorker' in navigator) {
  // If service workers are supported
} else if ('applicationCache' in window) {
  // Otherwise inject an iframe to use appcache
  var iframe = document.createElement('iframe');
  iframe.setAttribute('src', '/appcache.html');
  iframe.setAttribute('style', 'width: 0; height: 0; border: 0');

Either way, people are making full use of the offline nature of the book and that makes me very happy indeed.

ryanmcdermott/clean-code-javascript: Clean Code concepts adapted for JavaScript

This looks a sensible approach to writing clean JavaScript.

Sunday, January 1st, 2017

Typography Wars: Has the Internet Killed Curly Quotes? - The Atlantic

Glenn Fleishman on the war of attrition between primes and quotation marks on the web.

Monday, December 26th, 2016


An Enigma machine of one’s own.

Friday, December 16th, 2016

Experiment: Using Picture Element and VW+VH units as a Lightbox

This is a clever technique by Dave—use viewport units to make a lightweight lightbox.

Thursday, December 8th, 2016

Server Side React

Remy wants to be able to apply progressive enhancement to React: server-side and client-side rendering, sharing the same codebase. He succeeded, but…

In my opinion, an individual or a team starting out, or without the will, aren’t going to use progressive enhancement in their approach to applying server side rendering to a React app. I don’t believe this is by choice, I think it’s simply because React lends itself so strongly to client-side, that I can see how it’s easy to oversee how you could start on the server and progressive enhance upwards to a rich client side experience.

I’m hopeful that future iterations of React will make this a smoother option.

Monday, November 28th, 2016

Starting out

I had a really enjoyable time at Codebar Brighton last week, not least because Morty came along.

I particularly enjoy teaching people who have zero previous experience of making a web page. There’s something about explaining HTML and CSS from first principles that appeals to me. I especially love it when people ask lots of questions. “What does this element do?”, “Why do some elements have closing tags and others don’t?”, “Why is it textarea and not input type="textarea"?” The answer usually involves me going down a rabbit-hole of web archeology, so I’m in my happy place.

But there’s only so much time at Codebar each week, so it’s nice to be able to point people to other resources that they can peruse at their leisure. It turns out that’s it’s actually kind of tricky to find resources at that level. There are lots of great articles and tutorials out there for professional web developers—Smashing Magazine, A List Apart, CSS Tricks, etc.—but no so much for complete beginners.

Here are some of the resources I’ve found:

  • MarkSheet by Jeremy Thomas is a free HTML and CSS tutorial. It starts with an explanation of the internet, then the World Wide Web, and then web browsers, before diving into HTML syntax. Jeremy is the same guy who recently made CSS Reference.
  • Learn to Code HTML & CSS by Shay Howe is another free online book. You can buy a paper copy too. It’s filled with good, clear explanations.
  • Zero to Hero Coding by Vera Deák is an ongoing series. She’s starting out on her career as a front-end developer, so her perspective is particularly valuable.

If I find any more handy resources, I’ll link to them and tag them with “learning”.

Monday, November 21st, 2016

You Are Not Paid to Write Code – Brave New Geek

Gall’s Fundamental Theorem of Systems is that new systems mean new problems. I think the same can safely be said of code—more code, more problems. Do it without a new system if you can

A cautionary tale of the risks involved with embracing new frameworks.

But when you introduce a new system, you introduce new variables, new failure points, and new problems.

almost anything is easier to get into than out of.

Sunday, November 6th, 2016

Create a MarkDown tag - JSFiddle

This is nice example of a web component that degrades gracefully—if custom elements aren’t supported, you still get the markdown content, just not converted to HTML.

## Render some markdown!