JavaScript import maps are now supported cross-browser | Blog | web.dev
ES modules are a modern way to include and reuse JavaScript code in web applications. They are supported by modern browsers and provide several benefits over older, non-modular approaches to JavaScript development. A modern way to use ES modules is with the <script type="importmap"> tag. This tag allows you to define a mapping of external module names to their corresponding URLs, which makes it ea
The origin private file system | Articles | web.dev
Motivation When you think of files on your computer, you probably think about a file hierarchy: files organized in folders that you can explore with your operating system's file explorer. For example, on Windows, for a user called Tom, their To Do list might live in C:\Users\Tom\Documents\ToDo.txt. In this example, ToDo.txt is the filename, and Users, Tom, and Documents are folder names. `C:` on W
testing-library でユーザの気持ちになって書くフロントエンドのテスト
TL;DR フロントエンドのテストが壊れやすく要因の一つは、ユーザがどのようにソフトウェアを使うかをクエリに反映できていないからかも testing-library はソフトウェアを使うユーザの気持ちを反映させやすいようにクエリの優先度をつけていて、それに従うほうがいい 優先度の低いクエリも役に立つことがある 運用しているアクセシビリティなどの実装のガイドラインに沿うようなテストを作るとき アクセシビリティの低い実装をリファクタリングするためのテストを作るとき はじめに フロントエンドのテストに用いるツールとして testing-library が知られています。testing-library は提供しているクエリに優先度をつけています。この優先度は、どういう基準でつけられているのでしょうか。 この記事では、 testing-library のガイドを読みながら、クエリの優先度を「ユーザの
Experiments with the JavaScript Garbage Collector
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You Don't Need Rails to Start Using Hotwire
Update: I originally published this post few months ago, and it only covered Turbo Drive and Turbo Frames then, with a static site. I've since had a bunch of conversations with people working with other tech stacks (Rust, PHP, and Go) wanting to integrate Hotwire into their front-ends, and everyone kept asking about Turbo Streams, since it needs a back-end server. So I've updated the post to build
Sandboxing JavaScript Code
I've been enjoying playing around on Val Town lately. Val Town can be described a few ways; a cloud scripting site, a runnable github gists, or end-programmer programming. I first came across it in a Show HN thread. A "val" is a JavaScript/TypeScript function or value that runs on our servers. We aim to get you from idea to running code in seconds: type code, run it, get its API endpoint, schedule
JavaScript Import maps, Part 1: Introduction
We recently shipped import maps in Firefox 108 and this article is the first in a series that describes what they are and the problems they can solve. In this first article, we will go through the background and basics of import maps and follow up with a second article explaining more details of import maps. Background: JavaScript Modules If you don’t know JavaScript modules, you can read the MDN
Bringing Javascript to WebAssembly for Shopify Functions - Shopify
Bringing Javascript to WebAssembly for Shopify FunctionsWhile we’re working on getting our Shopify Functions infrastructure ready for the public beta, we thought we’d use this opportunity to shine some light on how we brought JavaScript to WebAssembly, how we made everything fit within our very tight Shopify Function constraints, and what our plans for the future look like. At Winter Editions 2023
Building Distributed Systems in Node
This post introduces the concept of durable execution, which is used by Stripe, Netflix, Coinbase, HashiCorp, and many others to solve a wide range of problems in distributed systems. Then it shows how simple it is to write durable code using Temporal's TypeScript/JavaScript SDK. For an updated version of this post, see durable-execution.pdf Distributed systems# When building a request-response mo
Fixing a Memory Leak in a Production Node.js App
Fixing a Memory Leak in a Production Node.js AppJanuary 12th, 2023 — 15 min read A few months ago, I wrote about my migration from Postgres to SQLite. I ended that with a "to be continued" because I had a number of issues related to memory and CPU spikes that I couldn't really explain. For a while I thought it was bugs in LiteFS (which I'm using to get distributed SQLite for my distributed node ap
Why Is My Jest Suite So Slow?
Our team is a couple of months into developing a new application, and our suite of unit 240 tests takes 46 seconds to run. That duration is not excessive yet, but it’s increasing in proportion to the number of tests. In a couple of months, it’ll take a couple of minutes to run our tests. We were surprised by this, as Jest is known for its fast performance. However, while Jest reported that each te
Why Not document.write()? – CSS Wizardry
10 January, 2023 (last updated on 1 June, 2025) Why Not document.write()? Written by Harry Roberts on CSS Wizardry. Table of Contents Independent writing is brought to you via my wonderful Supporters. What Makes Scripts Slow? The Preload Scanner document.write() Hides Files From the Preload Scanner What About Async Snippets? document.write() Executes Synchronously Is It All Bad? Early document.wri
eslint-cjs-to-esm: CJSをESMへとマイグレーションするツールを書いた
最近、色々なライブラリをCommonJS(CJS)からECMAScript Module(ESM)へとマイグレーションしています。 その際に、ESMでは__dirnameやrequireなどCommonJS特有の機能は使えなくなっています。 また、TypeScriptやBabelなど多くのツールはCJSではimport時に拡張子はなくても大丈夫ですが、ESMの場合はimport時に拡張子が必要になります。 import url from "node:url"; - import { mdEscape } from "./mdEscape"; + import { mdEscape } from "./mdEscape.js"; // ESMでは相対パスに拡張子は省略できない + const __filename = url.fileURLToPath(import.meta.url); /
Miško HeveryのQwik記事シリーズ | POSTD
古川陽介 株式会社リクルート プロダクト統括本部 プロダクト開発統括室 グループマネジャー 株式会社ニジボックス デベロップメント室 室長 Node.js 日本ユーザーグループ代表 複合機メーカー、ゲーム会社を経て、2016年に株式会社リクルートテクノロジーズ(現リクルート)入社。 現在はAPソリューショングループのマネジャーとしてアプリ基盤の改善や運用、各種開発支援ツールの開発、またテックリードとしてエンジニアチームの支援や育成までを担う。 2019年より株式会社ニジボックスを兼務し、室長としてエンジニア育成基盤の設計、技術指南も遂行。 Node.js 日本ユーザーグループの代表を務め、Node学園祭などを主宰。X: @yosuke_furukawaGithub: yosuke-furukawa
Reverse Engineering Tiktok's VM Obfuscation (Part 1)
TikTok has a reputation for its aggressive data collection. In fact, an article published on 22 December 2022 uncovered how ByteDance spied on multiple Forbes journalists using TikTok. While some of the data they collect may seem benign, it can be used to build a detailed profile of each user. Information such as user location, device type, and various hardware metrics are combined to create a uni
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https://blog.sentry.io/2023/02/23/sentrys-frontend-tests-migrating-from-enzyme-to-react-testing-library/
How to avoid tricky async state manager pitfalls in React—Martian Chronicles, Evil Martians’ team blog
core-js/docs/2023-02-14-so-whats-next.md at master · zloirock/core-js
Scrollend, a new JavaScript event | Blog | Chrome for Developers
Safe Data Fetching in Modern JavaScript
