Jeremy Keith

Jeremy Keith

Making websites. Writing books. Speaking at events. Living in Brighton. Working at Clearleft. Playing music. Taking photos. Answering email.

Journal 2484 sparkline Links 7481 sparkline Articles 70 sparkline Notes 3802 sparkline

Monday, June 18th, 2018

Praise for Going Offline

I’m very, very happy to see that my new book Going Offline is proving to be accessible and unintimidating to a wide audience—that was very much my goal when writing it.

People have been saying nice things on their blogs, which is very gratifying. It’s even more gratifying to see people use the knowledge gained from reading the book to turn those blogs into progressive web apps!

Sara Soueidan:

It doesn’t matter if you’re a designer, a junior developer or an experienced engineer — this book is perfect for anyone who wants to learn about Service Workers and take their Web application to a whole new level.

I highly recommend it. I read the book over the course of two days, but it can easily be read in half a day. And as someone who rarely ever reads a book cover to cover (I tend to quit halfway through most books), this says a lot about how good it is.

Eric Lawrence:

I was delighted to discover a straightforward, very approachable reference on designing a ServiceWorker-backed application: Going Offline by Jeremy Keith. The book is short (I’m busy), direct (“Here’s a problem, here’s how to solve it“), opinionated in the best way (landmine-avoiding “Do this“), and humorous without being confusing. As anyone who has received unsolicited (or solicited) feedback from me about their book knows, I’m an extremely picky reader, and I have no significant complaints on this one. Highly recommended.

Ben Nadel:

If you’re interested in the “offline first” movement or want to learn more about Service Workers, Going Offline by Jeremy Keith is a really gentle and highly accessible introduction to the topic.

Daniel Koskine:

Jeremy nails it again with this beginner-friendly introduction to Service Workers and Progressive Web Apps.

Donny Truong

Jeremy’s technical writing is as superb as always. Similar to his first book for A Book Apart, which cleared up all my confusions about HTML5, Going Offline helps me put the pieces of the service workers’ puzzle together.

People have been saying nice things on Twitter too…

Aaron Gustafson:

It’s a fantastic read and a simple primer for getting Service Workers up and running on your site.

Ethan Marcotte:

Of course, if you’re looking to take your website offline, you should read @adactio’s wonderful book

Lívia De Paula Labate:

Ok, I’m done reading @adactio’s Going Offline book and as my wife would say, it’s the bomb dot com.

If that all sounds good to you, get yourself a copy of Going Offline in paperbook, or ebook (or both).

My biggest challenge with JavaScript | Go Make Things

This really, really resonates with me:

I think the thing I struggle the most with right now is determining when something new is going to change the way our industry works for the better (like responsive web design did 5 or 6 years ago), and when it’s just a fad that will fade away in a year or three (which is how I feel about our obsession with things like Angular and React).

I try to avoid jumping from fad to fad, but I also don’t want to be that old guy who misses out on something that’s an important leap forward for us. I spend a lot of time thinking about the longer term impact of the things we make (and make with).

Sunday, June 17th, 2018

Detecting image requests in service workers

In Going Offline, I dive into the many different ways you can use a service worker to handle requests. You can filter by the URL, for example; treating requests for pages under /blog or /articles differently from other requests. Or you can filter by file type. That way, you can treat requests for, say, images very differently to requests for HTML pages.

One of the ways to check what kind of request you’re dealing with is to see what’s in the accept header. Here’s how I show the test for HTML pages:

if (request.headers.get('Accept').includes('text/html')) {
    // Handle your page requests here.
}

So, logically enough, I show the same technique for detecting image requests:

if (request.headers.get('Accept').includes('image')) {
    // Handle your image requests here.
}

That should catch any files that have image in the request’s accept header, like image/png or image/jpeg or image/svg+xml and so on.

But there’s a problem. Both Safari and Firefox now use a much broader accept header: */*

My if statement evaluates to false in those browsers. Sebastian Eberlein wrote about his workaround for this issue, which involves looking at file extensions instead:

if (request.url.match(/\.(jpe?g|png|gif|svg)$/)) {
    // Handle your image requests here.
}

So consider this post a patch for chapter five of Going Offline (page 68 specifically). Wherever you see:

if (request.headers.get('Accept').includes('image'))

Swap it out for:

if (request.url.match(/\.(jpe?g|png|gif|svg)$/))

And feel to add any other image file extensions (like webp) in there too.

Checked in at The Burren. Sunday session — with Jessica map

Checked in at The Burren. Sunday session — with Jessica

Saturday, June 16th, 2018

On Rejection | Zeldman on Web & Interaction Design

The focus of the A Book Apart series is what makes it great …and that means having to reject some proposals that don’t fit. Even though I’ve had the honour of being a twice-published A Book Apart author, I also have the honour of receiving a rejection, which Jeffrey mentions here:

In one case we even had to say no to a beautifully written, fully finished book.

That was Resilient Web Design.

So why did we turn down books we knew would sell? Because, again—they weren’t quite right for us.

It was the right decision. And this is the right advice:

If you’ve sent us a proposal that ultimately wasn’t for us, don’t be afraid to try again if you write something new—and most importantly, believe in yourself and keep writing.

Friday, June 15th, 2018

Thursday, June 14th, 2018

Wednesday, June 13th, 2018