JavaScript eventing deep dive | Articles | web.dev
Event.stopPropagation() and Event.preventDefault() JavaScript event handling is often straightforward. This is especially true when dealing with a simple (relatively flat) HTML structure. Things get a bit more involved though when events are traveling (or propagating) through a hierarchy of elements. This is typically when developers reach for stopPropagation() or preventDefault() to solve the pro
JavaScriptのIterator / Generatorの整理
目的と対象読者 IteratorとIterableとGeneratorとGenerator Functionの区別が曖昧な人 (記事前半) Generatorの制御フローを完全理解したい人 (記事後半) の理解を深めるための記事です。 まとめ IteratorとIterableの関係 Iteratorは狭義には呼び出し元の next 呼び出しに応じて要素を出力するインターフェースである。 IterableはIteratorを生成するインターフェースである。 IterableだからといってIteratorとは限らず、IteratorだからといってIterableとは限らない。しかし実際には多くのIteratorはIterableのインターフェースも実装している。 Iterableとコレクションは相互変換可能である。 Iterableは for-of ループで処理できる。 IteratorとG
Why WASM is not the future of Babylon.js
(at least for now)… We recently got pinged on Twitter regarding a question about WebAssembly (WASM) being the future of Babylon.js. Here is our response: Our friends at Three.js had the same answer by the way :) I wanted to use this blog to get more into details about why we do not think WASM is the future of JavaScript frameworks. WASM is a target not a user facing languageWASM is meant to be a w
'return await promise' vs 'return promise' in JavaScript
Is there any difference between using 'return await promise' and 'return promise' in asynchronous JavaScript functions?
Don't attach tooltips to document.body
09 Mar, 2021 TL;DRInstead of attaching tooltips directly to document.body, attach them to a predefined div in document.body. BAD <body> <!-- temporary div, vanishes when tooltips vanishes --> <div>my tooltip</div> <body> <body> <!-- this div stays forever, just for attaching tooltips --> <div id="tooltips-container"> <!-- temporary div, vanishes when tooltips vanishes --> <div>my tooltip</div> </d
JavaScript Development: Making a Web Worker optional
In case you have a lot of JavaScript related logic running inside a main thread or a Web Worker, it makes perfect sense to move expensive logic into another worker. Workers run inside a different thread using their own CPU if possible. However, there can be use cases where in some scenarios there is a lot of JS related workload on a given thread, while in other scenarios this thread is mostly idle
Modern web apps without JavaScript bundling or transpiling
August 12, 2021 Modern web apps without JavaScript bundling or transpiling I didn't much care for vanilla JavaScript prior to ES6. Through all of the 2000s, I chased different approaches to avoid writing too much of it. First there was RJS (Ruby-to-JavaScript). Then there was CoffeeScript. Both transpiling approaches that turned more enjoyable-to-write source code into the kind of JavaScript that
JavaScript needs more helper functions for iteration (map, filter, etc.) – where should we put them?
JavaScript needs more helper functions for iteration (map, filter, etc.) – where should we put them? Iteration is a standard that connects operations with data containers: Each operation that follows this standard, can be applied to each data container that implements this standard. In this blog post: We first explore three questions: How does JavaScript’s iteration work? What are its quirks? What
GraphQLクライアントにurqlをおすすめしたい
GraphQLのクライアントといえばApollo Clientが使われることが多いと思いますが、urqlというクライアントをおすすめする記事です。 TL;DR urqlのドキュメントキャッシュはApolloみたいなキャッシュ管理が要らなくて楽だからおすすめ ドキュメントキャッシュは、Mutationの __typename を見て汚れたキャッシュを捨てる仕組み Mutationのあと refetchQueries やってるならそれはurqlが自動でやってることと同じ なぜurqlをおすすめするのか この記事ではurqlのドキュメントキャッシュというキャッシュを仕組みだけを紹介します。雑に言うと、Apolloの正規化されたキャッシュより多少効率は落ちるものの煩雑な正規化されたキャッシュの管理から解き放たれるというものです。Apolloのキャッシュの管理に疲れた人にめちゃくちゃおすすめですし、
How to Eliminate Render-Blocking Resources: a Deep Dive
You might be here because Lighthouse told you to "eliminate render-blocking resources". Render-blocking resources are a common hurdle to rendering your page faster. They impact your Web Vitals which now impact your SEO. Slow render times also frustrate your users and can cause them to abandon your page. I worked with one client to reduce their render-blocking resources and improved their site load
Fastly Launches Highly-Secure Serverless JavaScript | Fastly
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URLPattern brings routing to the web platform | Web Platform | Chrome for Developers
Published: July 22, 2021 Routing is a key piece of every web application. At its heart, routing takes a URL, applies a pattern matching or other app-specific logic to it, and then, usually, displays web content based on the result. Routing might be implemented in a number of ways: Server code that maps paths to files on a disk Logic in a single-page app that waits for changes to the current locati
The Road to Ember 4.0
Contributors to the Ember project have been hard at work since Ember Octane was released in December 2019. Over the duration of a challenging (and sometimes devastating) year and a half, we've shipped a powerful new feature (Named Blocks) and supported an ecosystem shifting to Octane conventions. We've more closely aligned Ember with wider frontend conventions through improved publishing & build t
Image To Text Conversion With React And Tesseract.js (OCR) — Smashing Magazine
Do you have to process data manually because it is served through images or scanned documents? An image-to-text conversion makes it possible to extract text from images to automate the processing of texts on images, videos, and scanned documents. In this article, we look at how to convert an image to text with React and Tesseract.js(OCR), preprocess images, and deal with the limitations of Tessera
Encoding data for POST requests
Right now, when you go to copilot.github.com you're greeted with this example: async function isPositive(text) { const response = await fetch(`http://text-processing.com/api/sentiment/`, { method: 'POST', body: `text=${text}`, headers: { 'Content-Type': 'application/x-www-form-urlencoded', }, }); const json = await response.json(); return json.label === 'pos'; } This is bad and might result in sec
Temporal: getting started with JavaScript’s new date time API
Temporal: getting started with JavaScript’s new date time API Updates: 2022-01-10: Temporal.now was renamed to Temporal.Now. 2021-06-30: Rearranged the content and created a section on the concepts and patterns used by the Temporal API. 2021-06-29: Clarified how Instant uses the ISO-8601 calendar. Listed the properties of some classes. Date, JavaScript’s current date time API is infamously difficu
Demystifying styled-components • Josh W. Comeau
Filed underReactoninJune 21st, 2021.Jun 2021.Last updatedoninJuly 17th, 2025.Jul 2025. When I first started using styled-components, it seemed like magic ✨. Somehow, using an obscure half-string-half-function syntax, the tool was able to take some arbitrary CSS and assign it to a React component, bypassing the CSS selectors we've always used. Like so many devs, I learned how to use styled-componen
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用 ts-migrate 仙女棒讓 JS 專案瞬間migrate 成 TypeScript
(PDF) COSMICDUKE Cosmu with a twist of MiniDuke - F-Secure
Benchmarking JavaScript memory usage
