ただし、種別は以下の通りです。 prefix (前置演算子) …… もとの式の手前に何個でもつけられる演算子。 例: -~-~x postfix (後置演算子) …… もとの式の直後に何個でもつけられる演算子。 例: x.foo()`bar`[0] postfix once …… もとの式の直後に1個だけつけられる演算子。 例: x++ は可能だが x++-- はパースされない。 逆に ++--x はパースされるが、構文とは別のルールで禁止される。 (後述) infixL …… 中置演算子で左結合 (演算子の優先度が同じ場合は左側にあるほうが優先される) 例: 0.1 + 1.0 - 1.0 は (0.1 + 1.0) - 1.0 になる infixR …… 中置演算子で左結合 (演算子の優先度が同じ場合は右側にあるほうが優先される) 例: 2 ** 2 ** 3 は 2 ** (2 **
Defensive CSS
I spent years teaching CSS layout on this blog. I put everything I know into The Layout Maestro course: 70+ lessons and 150+ interactive examples that teach you how to think CSS layouts, not just memorize syntax. 👋 This article has been expanded into a new project called Defensive CSS. Due to the fact that the content here will not be updated, I recommend you to read defensivecss.dev instead. Oft
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自己紹介 業務委託でestieに参画している@HirokiOmoteです。 estieでは主にデザインとFrontendを担当しています。 過去には、スタートアップの創業フェーズでプロダクトの立ち上げなども行なっていました。 そこでは、Nuxt + Firebaseを採用し、Webアプリの制作に着手。 しかし、プロダクトが成長するにつれ、コードの安全性や可読性の観点からJavaScript…動的型付け言語の限界を感じていました。 そして、静的型付け言語であるTypeScriptを採用することに。 また、Firebase Cloud Functionsを使った機能開発も行うようになり、次第にBackendもTypeScriptを使って書くようになりました。 それが、TypeScriptとの出会いです。 気づけば、すっかりその魅力に取りつかれていました。TypeScriptは楽しい。 そもそも
はじめに 「enumはツリーシェイキングができないからas constを使え。」TypeScriptプロジェクトでよく聞くアドバイスだ。リントルールで強制するチームもあれば、コードレビューで指摘されることもある。 しかし実際のところ、enum数個がバンドルサイズに与える影響は微々たるものだ。パフォーマンスの話だけでは、なぜここまで推奨されているのか説明がつかない。namespaceやparameter propertiesのように、パフォーマンスとは無関係な構文も同じ文脈で非推奨とされているのはなぜだろうか？ この記事は、その疑問から出発する。 TypeScript初期：JavaScriptにないものを独自に作っていた時代 TypeScriptが初めて登場した2012年、JavaScriptは今とはかなり違っていた。ES Modules（import/export）は標準化されておらず、ク
Assessing Claude Mythos Preview’s cybersecurity capabilities April 7, 2026 Nicholas Carlini, Newton Cheng, Keane Lucas, Michael Moore, Milad Nasr, Vinay Prabhushankar, Winnie Xiao Hakeem Angulu, Evyatar Ben Asher, Jackie Bow, Keir Bradwell, Ben Buchanan, David Forsythe, Daniel Freeman, Alex Gaynor, Xinyang Ge, Logan Graham, Kyla Guru, Hasnain Lakhani, Matt McNiece, Mojtaba Mehrara, Renee Nichol, A
ライブラリ作者におすすめしたいBabelの新機能 babel-plugin-polyfill-corejs3 | Wantedly Engineer Blog
Babelの新しいpolyfill用プラグインであるbabel-polyfillsが2022年4月に脱experimentalを果たしていました。そこで本稿では、Babelにおいてpolyfillがどのように扱われていたかを振り返りながら新しいpolyfill pluginを紹介します。 注意: Babel 7.4で非推奨化された@babel/polyfillとは別物です。 何が問題だったのか?babel-polyfillsのREADMEと元issueにも説明がありますが、本記事ではあらためて日本語で説明したいと思います。端的に言うと今までは以下の要件を両立できませんでした。 ソースコード中で使われている機能のpolyfillだけを注入する。ターゲットブラウザを指定して、必要なpolyfillだけを注入する。副作用のない形でpolyfillを注入する。babel-polyfillsはこれら
WebKit Features in Safari 17.0
Sep 18, 2023 by Jen Simmons and the Safari / WebKit Team Today’s the day for Safari 17.0. It’s now available for iOS 17 and iPadOS 17. [Update September 26th] And now, Safari 17.0 is available for macOS Ventura, and macOS Monterey, and macOS Sonoma. Safari 17.0 is also available in the vision OS Simulator, where you can test your website by downloading the latest beta of Xcode 15, which supports t
ECMAScript Record & Tuple polyfill はどのようにして実装されているのか | Wantedly Engineer Blog
Record & Tuple とはRecord & Tuple は ECMAScript (JavaScript) に対する提案段階の機能で、構造化データのためのプリミティブ型を提供するというものです。RecordはObjectのプリミティブ版、TupleはArrayのプリミティブ版にあたります。 プリミティブとオブジェクトJavaScriptにおける値はプリミティブとオブジェクトの2種類に分けられます。 プリミティブはイミュータブルで、値の同等性にもとづいて比較されます。既存のプリミティブとして、null, undefined, number, string, boolean, bigint, symbol が存在しています。オブジェクトはデフォルトでは書き換え可能で、参照の同一性にもとづいて比較されます。これまで、複数のスカラー値をまとめて構造化データとして扱うには、オブジェクト (主
All JavaScript and TypeScript Features of the last 3 years
TypeScript as envisioned by Stable DiffusionThis article goes through almost all of the changes of the last 3 years (and some from earlier) in JavaScript / ECMAScript and TypeScript . Not all of the following features will be relevant to you or even practical, but they should instead serve to show what’s possible and to deepen your understanding of these languages. There are a lot of TypeScript fe
CUPID: for joyful coding
What started as lighthearted iconoclasm, poking at the bear of SOLID, has developed into something more concrete and tangible. If I do not think the SOLID principles are useful these days, then what would I replace them with? Can any set of principles hold for all software? What do we even mean by principles? I believe that there are properties or characteristics of software that make it a joy to
ESLint v9.x end-of-life is 2026-08-06 and will not be maintained after that. Upgrade or consider long-term support options Published 05 Apr, 2024 under Release Notes ESLint v9.0.0 released We just pushed ESLint v9.0.0, which is a major release upgrade of ESLint. This release adds some new features and fixes several bugs found in the previous release. This release also has some breaking changes, so
Patterns for Building LLM-based Systems & Products [ llm engineering production 🔥 ] · 66 min read Discussions on HackerNews, Twitter, and LinkedIn “There is a large class of problems that are easy to imagine and build demos for, but extremely hard to make products out of. For example, self-driving: It’s easy to demo a car self-driving around a block, but making it into a product takes a decade.”
Prettier 3.6: Experimental fast CLI and new OXC and Hermes plugins! · Prettier
This release includes several important feature additions that we're excited to share with you. First, we're shipping a new experimental high-performance CLI behind a feature flag (--experimental-cli). This CLI was previously only available in prettier@next, but now you can enable it simply by using a flag. We encourage you to try it out and share your feedback! If you are interested in the intern
Jun 6, 2023 by Patrick Angle, Jean-Yves Avenard, Marcos Caceres, Ada Rose Cannon, Eric Carlson, Garrett Davidson, Jon Davis, Karl Dubost, Brady Eidson, Matthew Finkel, Simon Fraser, Brent Fulgham, Rachel Ginsberg, David Johnson, Anne van Kesteren, Mark Lam, Sihui Liu, Justin Michaud, Jer Noble, Tim Nguyen, Ben Nham, Richard Robinson, Michael Saboff, Alexey Shvaika, Jen Simmons, Sam Sneddon, Brando
The proposal “Pipe operator (|>) for JavaScript” (by J. S. Choi, James DiGioia, Ron Buckton and Tab Atkins) introduces a new operator. This operator is an idea borrowed from functional programming that makes applying functions more convenient in many cases. This blog post describes how the pipe operator works and what its use cases are (there are more than you might expect!). The two competing pro
Blogged Answers: My Experience Modernizing Packages to ESM
Random musings on React, Redux, and more, by Redux maintainer Mark "acemarke" Erikson This is a post in the Blogged Answers series. Details on the painful experiences and hard-earned lessons I've learned migrating the Redux packages to ESM Table of Contents 🔗︎ Introduction Redux Packages Background Packages and Configurations Issue History Early Attempts Migrating to Vitest Initial Alpha Testing
JavaScript APIs You Don’t Know About — Smashing Magazine
In this article, Juan Diego covers the least known yet extremely useful APIs, such as the Page Visibility API, Web Sharing API, Broadcast Channel API and Internationalization API. Together we will see what they are, where we should use them, and how to use them. A couple of days ago, I revisited the awesome 2021 State of JS Survey. The state of JS is an online survey that collects data from develo
--- name: skill-creator description: Guide for creating effective skills. This skill should be used when users want to create a new skill (or update an existing skill) that extends Claude's capabilities with specialized knowledge, workflows, or tool integrations. license: Complete terms in LICENSE.txt --- # Skill Creator This skill provides guidance for creating effective skills. ## About Skills S
WebKit Features for Safari 26.2
Safari 26.2 is a big release. Packed with 62 new features, this release aims to make your life as a web developer easier by replacing long-standing frustrations with elegant solutions. You’ll find simpler ways to create common UI patterns with just a few lines of HTML or CSS, and no JavaScript — like auto-growing text fields with CSS field-sizing, and buttons that open/close dialogs and popovers w
Tech Solvency: The Story So Far: CVE-2021-44228 (Log4Shell log4j vulnerability).
Log4Shell log4j vulnerability (CVE-2021-44228 / CVE-2021-45046) - cheat-sheet reference guide Last updated: $Date: 2022/02/08 23:26:16 $ UTC - best effort, validate all for your environment/model before use, unofficial sources may be wrong by @TychoTithonus (Royce Williams), standing on the shoulders of many giants Send updates or suggestions (please include category / context / public (or support
Rust from 0 to 80% for JavaScript Developers - Michael Salim | Senior Full Stack Freelancer and Startup Founder
This is a list of topic that will help you understand Rust quickly if you are a JavaScript developer. There are a lot of tutorial that start from scratch. But if you already know something else, why not compare them? These are differences that I wished I could refer to before starting Rust, kept short. Disclaimer! I’m very far from being well versed in Rust. These are how I interpret them and no m
Lodash is dead. Long live Radash.
Lodash is old and lame, Radash is new and kool. What more do you need to know? What’s wrong with Lodash?In a time when Javascript’s dynamic abilities were held as a feature instead of a bug, Lodash was made to be as helpful as possible by providing functions that behave differently given different inputs. These days, we know better. Functional concepts like pure functions, deterministic behavior,
#Tags | blog.jxck.io
1password 2025-11-13 1Password AC #10: SSH と Git コミット署名 2025-11-12 1Password AC #9: Travel Mode 2025-11-11 1Password AC #8: 1Password CLI 2025-11-10 1Password AC #7: Group と Vault の運用 2025-11-09 1Password AC #6: Business アカウント特典の無料 Family アカウント 2025-11-08 1Password AC #5: 1Password アカウントへの 2FA 2025-11-07 1Password AC #4: Secret Key の運用とアカウントリカバリ 2025-11-06 1Password AC #3: Master Password の作り方 202
{ "name": "sample-4.0.3", "version": "0.1.0", "private": true, "dependencies": { "@testing-library/jest-dom": "^5.11.4", "@testing-library/react": "^11.1.0", "@testing-library/user-event": "^12.1.10", "@types/jest": "^26.0.15", "@types/node": "^12.0.0", "@types/react": "^17.0.0", "@types/react-dom": "^17.0.0", "react": "^17.0.2", "react-dom": "^17.0.2", "react-scripts": "4.0.3", "typescript": "^4.
Prettier 3.1: New experimental ternaries formatting and Angular control flow syntax! · Prettier
This release adds indentation back to nested ternaries along with a new --experimental-ternaries flag to try a more novel "curious ternary" format that scales better to deeply nested conditionals. We are keen for your feedback on the experimental format before it rolls out as the default behavior later this year! We have also added support for the control flow syntax in Angular v17. For details on
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JavaScript Best Practices | The WebStorm Blog
デザインからTypeScriptと仲良くなってみる。 - estie inside blog
TypeScriptはなぜランタイム構文を作り、なぜ今それを取り除きつつあるのか
Claude Mythos Preview \ red.anthropic.com
ESLint v9.0.0 released - ESLint - Pluggable JavaScript Linter
Patterns for Building LLM-based Systems & Products
News from WWDC23: WebKit Features in Safari 17 beta
A pipe operator for JavaScript: introduction and use cases
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バージョン指定してcreate-react-appを実行 - Qiita