Simon Willison’s Weblog

Items tagged javascript in Jun

Filters: Month: Jun × javascript ×


Refactoring optional chaining into a large codebase: lessons learned (via) JavaScript now supports foo?.bar?.baz?.() optional chaining syntax across all major browsers. Lea Verou provides the definitive guide to using it to refactor code. # 18th June 2020, 3:23 pm

When should you be using Web Workers? 85% of worldwide mobile devices are massively less performant than high end iPhones. Surma argues that we should be making aggressive use of Web Workers to keep as much of our JavaScript as possible off the main UI thread, to avoid freezing up the entire interface. # 15th June 2019, 4:31 am

source-map-explorer. Very neat tool for creating a tree map visualization of the size of the components of a bundled JavaScript file created by webpack (or if you’re using create-react-app by “npm run build”). I ran this using “npx source-map-explorer build/static/js/main.d63f3f34.js” (since I don’t like using “npm install -g”). # 24th June 2018, 9:37 pm

Notebook: How to build a Teachable Machine with TensorFlow.js (via) This is a really cool Observable notebook. It explains how to build image classification that runs in the browser on top of Tensorflow.js, and includes interactive demos that hook into your webcam and let you hold up items and use them to train a classifier. Since it’s built on Observable every single underlying line of source code is available to browse as part of the essay. # 20th June 2018, 9:10 pm

Changelog 2018-06-12 / Observable. The ability to download an Observable notebook as a stand-alone ES module and run it anywhere using their open source runtime is fascinating, but it’s also worth reading the changelog for some of the new clever tricks they are pulling using await—“await visibility();” in a notebook cell will cause execution to pause until the cell scrolls into view for example. # 13th June 2018, 3:50 pm

jQuery.queueFn. “Execute any jQuery method or arbitrary function in the animation queue”. I’m surprised this isn’t baked in to jQuery itself—the plugin is only a few lines of code. # 30th June 2010, 12:59 pm

pdf.js. A JavaScript library for creating simple PDF files. Works (flakily) in your browser using a data:URI hack, but is also compatible with server-side JavaScript implementations such as Node.js. # 17th June 2010, 7:39 pm

Parsing file uploads at 500 mb/s with node.js. Handling file uploads is a real sweet spot for Node.js, especially now it has a high performance Buffer API for dealing with binary chunks of data. Felix Geisendörfer has released a new library called “formidable” which makes receiving file uploads (including HTML5 multiple uploads) easy, and uses some clever algorithmic tricks to dramatically speed up the processing of multipart data. # 2nd June 2010, 3:57 pm

Firefox 3.5 for developers. It’s out today, and the feature list is huge. Highlights include HTML 5 drag ’n’ drop, audio and video elements, offline resources, downloadable fonts, text-shadow, CSS transforms with -moz-transform, localStorage, geolocation, web workers, trackpad swipe events, native JSON, cross-site HTTP requests, text API for canvas, defer attribute for the script element and TraceMonkey for better JS performance! # 30th June 2009, 6:08 pm

Unimpressed by NodeIterator. John Resig, one of the most talented API designers I’ve ever come across, posts some well earned criticism of the document.createNodeIterator DOM traversal API. # 19th June 2009, 9:53 pm

SWFUpload jQuery Plugin. Nice looking plugin around an invisible Flash shim that provides multiple file uploads and client-side progress indicators. # 16th June 2009, 11:46 am

Opera Unite. Opera’s big announcement: a developer preview (“labs release”) of their new web-server-in-your-browser feature, Unite. Includes an Opera-hosted proxy to help break through your firewall. The web server can be customised using server-side JavaScript running in an Opera Widget. # 16th June 2009, 11 am

Mapstraction API Sandbox. Andrew Turner’s new tool for exploring the Mapstraction JavaScript library, which provides a unified code interface to 12 different mapping services # 7th June 2009, 11:41 am

Javascript protocol fuzz results. If your HTML sanitizer uses blacklisting rather than whitelisting here are a few more weird ways of injecting javascript: in to a link that you need to worry about—but you should really switch to whitelisting http:// and https:// instead. # 30th June 2008, 3:57 pm

Module Pattern Provides No Privacy... at least not in JavaScript(TM) (via) JavaScript variables hidden inside a closure aren’t as hidden as I thought—it turns out you can pass a closure as the second argument to eval (at least in Firefox) and “steal” private variables back out of it. # 27th June 2008, 7:01 pm

BUG: XSS Security flaw in BaseCamp Messages (via) BaseCamp lets users include HTML and JavaScript in messages, on the basis that anyone with a BaseCamp account is a trusted party. I’m not convinced: you could use this to circumvent BaseCamp’s access control stuff and read messages you’re not meant to. On the flip side, you could also use this to add brand new features to BaseCamp by using JavaScript in a message as a server-side equivalent to Greasemonkey. # 26th June 2008, 9:39 am

jsontime. Nat and I threw this together this morning—it runs on Google App Engine and exposes Python’s pytz timezone library over JSONP. # 21st June 2008, 7:07 pm

When Bugs Collide: Fixing Text Dimming in Firefox 2. Handy tips from Drew on fixing the glitchy text rendering in Firefox 2 when you animate opacity without breaking alpha-transparent PNGs in IE6. # 19th June 2008, 6:09 pm

Deep Profiling jQuery Apps. Neat plugin from John Resig that monkey-patches most (all?) of the jQuery methods to build up a detailed profile of which methods are being used by a given page. # 16th June 2008, 10:20 am

Spicing Up Embedded JavaScript. John Resig collects the various ways in which a JavaScript interpreter can be hosted by Python, PHP, Perl, Ruby and Java. There are full JS implementations in PHP, Perl and Java; Ruby and Python both have modules that use an embedded SpiderMonkey. # 15th June 2008, 11:32 am

Is It OK to Require JavaScript? Not if you can avoid doing so. Unobtrusive JavaScript really isn’t hard if you design it in from the start, and since stackoverflow is a community forum / questions and answers site I have trouble imagining a feature that can’t be made to work without JavaScript. # 10th June 2008, 6:41 am

OS OpenSpace from Ordnance Survey (via) Ordinance Survey now provide a free JavaScript mapping API for “non-commercial purposes” by “private individuals”. The maps look incredibly detailed, although I can’t find any live API demos on the site (the documentation is illustrated with screenshots). # 9th June 2008, 8:30 am

Updated jQuery Bookmarklet. Nicer than my own “Inject jQuery” bookmarklet because it drops in a temporary message confirming that jQuery has been imported (or telling you that jQuery was already present). # 8th June 2008, 8:46 pm

An interview with 280 North on Objective-J and Cappuccino. Fantastic comment thread with involvement from the guys who created Objective-J. Just like Objective-C, Objective-J is a preprocessor that runs against regular JavaScript source files so you can use JavaScript and Objective-J idioms interchangeably. # 7th June 2008, 7:40 pm

280slides and Objective-J. 280 slides uses an Objective-C clone written in 13KB of JavaScript. I have to admit I’m completely baffled as to why you would want to use Objective C instead of JavaScript, but evidently it worked fantastically well for them. # 7th June 2008, 4:09 pm

SquirrelFish. WebKit’s JavaScript engine was no slouch, but that hasn’t stopped them from replacing it with a brand new “register-based, direct-threaded, high-level bytecode engine, with a sliding register window calling convention”. It runs 1.6x faster and has the Best Logo Ever. # 3rd June 2008, 7:57 am

jQuery plugin: Validation. Pretty clever way of attacking the client-side form validation problem; supports both configuration object literals and custom attributes on the form fields themselves. # 30th June 2007, 10:26 pm

[...] Silverlight has full access to the browser DOM and you can make calls from Javascript into silverlight code and from Silverlight into Javascript. This means that you can already write the presentation layer of a client side web app in Javascript and implement your business logic in IronPython.

Michael Foord # 16th June 2007, 12:25 am

A JavaScript Module Pattern. I’ve been using this pattern for a few months—it works really well, though I tend to keep my own code in my own namespace rather than adding it to YAHOO. # 12th June 2007, 11:30 pm

google-diff-match-patch (via) Robust algorithms to perform the operations required for synchronizing plain text, in Java, JavaScript and Python. # 9th June 2007, 6:15 pm