JavaScript on roderick.dk

Announcing idempot-js: Idempotency Middleware for Node.js, Bun, and Deno

Mon, 06 Apr 2026 11:15:53 +0000

Introducing idempot-js — IETF-compliant idempotency middleware for Express, Fastify, and Hono with pluggable storage backends.

The reduce ({...spread}) anti-pattern

Tue, 21 Dec 2021 09:50:00 +0100

I thought this was a really interesting examination of the performance penalties of using ({...spread}) in JavaScript.

Link: The reduce ({…spread}) anti-pattern

JSDoc typings: all the benefits of TypeScript, with none of the drawbacks

Tue, 20 Jul 2021 14:30:00 +0200

An in depth exploration of how far you can get with using JSDoc (and the TypeScript compiler) without resorting to writing TypeScript or having a build step in your project.

Link: JSDoc typings: all the benefits of TypeScript, with none of the drawbacks

The (extremely) loud minority

Thu, 12 Nov 2020 20:58:00 +0100

It’s understandable to think that JavaScript frameworks and their communities are eating the web because places like Twitter are awash with very loud voices from said communities. Always remember that although a subset of the JavaScript community can be very loud, they represent a paltry portion of the web as a whole. This means that when they say something like “CSS sucks” — what they mean is “CSS sucks for a small subset of less than 1 percent of the web”.

Avoid double exclamations in JavaScript

Mon, 10 Sep 2018 00:00:00 +0000

There is a common misuse of JavaScript’s type coercion that I see in code reviews. It’s the terse use of two exclamation marks to convert a truthy value to a Boolean value.

Here’s an example:

const someValue = "I like apple pie";
const userLikesPie = !!someValue;
// userLikesPie is now `true`

I think this is a misuse for two reasons:

jQuery Data Link considered harmful

Wed, 03 Nov 2010 00:00:00 +0000

“Considered harmful” has always been good link bait.

I am not trying to start a flamewar, but merely express my concerns over the recent decisions of the jQuery team to actively endorse plugins that deserves no special treatment from any other plugins out there.

If you have different opinions, please do respond in the comments or write a blog post expressing them.

Introducing PubSubJS, a library for doing publish/subscribe in JavaScript

Tue, 12 Oct 2010 00:00:00 +0000

For quite a while, I have been working on a large web application for a client. For publish/subscribe style messaging in the web frontend, we use jQuery custom events triggered on the body element. This is quite a neat trick to ensure loose coupling of modules, since you’re really just tracking what the user does, and not what module happened to generate the message.

Introducing FailFast, a JavaScript library for failure

Thu, 02 Sep 2010 00:00:00 +0000

Tomorrow I will be attending dConstruct 2010, which I am very excited about. I flew in a day early, so I could get some time to enjoy Brighton. One of the first stops has been The Skiff, “a nice little place to work in the middle of Brighton”.

The Skiff is indeed a very nice place: very few interruptions and very friendly people. While sitting at my visitors desk, I’ve managed to finally finish a little JavaScript library, that has been a very long time in the making: FailFast. All it took was tidying up the documentation and writing the last few missing unit tests.

IE8 Getting EcmaScript 262 rev. 5 Compliant Native JSON

Fri, 26 Feb 2010 00:00:00 +0000

Earlier this week, Microsoft posted an article with details on udpates to the native JSON implementation in IE8.

Because of the new ECMAScript specification changes, some customers have reported issues. These issues are caused by deviations between the native JSON feature in Internet Explorer 8 and the final specification. An update is now available to address these customer issues and improve JSON interoperability of Internet Explorer 8. This update enables JSON interoperability of Internet Explorer 8 to keep in conformance with the new “ECMAScript, fifth edition” standard specification.

Combining JavaScript Files - Juicer vs Sprockets

Sun, 04 Oct 2009 00:00:00 +0000

Currently working on a project that has well defined use of “namespaces” and structured use folders for its JavaScript files. I wanted to investigate the options for combining and minifying JavaScript files.

I need a tool that:

can be run from command line (my team uses many different editors and IDEs)
will work on both Windows and Unix based platforms
does not require huge, obscure configuration files
can merge sources recursively
has an acceptable software license (MIT / Apache / BSD)
is thorougly tested
is extensible
can work with any JavaScript framework

I settled for trying out Juicer and Sprockets, since both tools met the requirements and were the only high-quality tools on my radar.

TextMate snippet for creating Low Pro Behaviors

Sun, 16 Aug 2009 00:00:00 +0000

Behaviours

To encapsulate complex javascript behaviour on websites, I have been using Dan Webb’s Low Pro library for several years. Low Pro allows you to create self-contained Behavior classes, which avoids polluting the global namespace with variables and makes for very easy re-use of code.

I’ve previously given a little introduction to Low Pro for Prototype at a local Meetup event, where I show an example of creating your own behaviours.

LowPro Updated for Firefox 3.5

Thu, 02 Jul 2009 00:00:00 +0000

Firefox 3.5 was recently released, and offers significant updates. If you have not upgraded yet, you should do so now.

In the LowPro community, we have been tracking compatibility with the upcoming Firefox. The existing LowPro was compatible with Firefox 3.5RC2, but incompatible with the final release of Firefox 3.5.

So, if you are using LowPro, you should upgrade with a new version of LowPro today.

Introduction to Low Pro for Prototype

Thu, 07 May 2009 00:00:00 +0000

Tonight I gave a lightweight introduction to Low Pro for Prototype at the Öresund JavaScript meetup.

For those that missed it, or just want to study the example again, you can see the slides as a PDF, see the sample or download a zip file with everything.

The meetup was very informal and there were also two other presentations: Mats Bryntse gave an overview of “What’s new in EcmaScript 3.1” and Rasmus Olausson showed us a “Hello world with Google Web Toolkit” as well as how to beat his Sudoku webapp :-)

IE6 Background flicker once again

Fri, 27 Mar 2009 00:00:00 +0000

Every once in awhile you come across one of those Internet Explorer 6 issues that tries it’s hardest to be really annoying. Today was one of those days with IE.

Having flown out to work directly with a client’s web team yesterday, I spent some time today cursing at IE6 and trying to deal with a weird flickering of the webpage, apparently caused by hovering over a menu.