babel-preset-env@2.0 を試した -トランスパイル環境をスケールさせていく -
こんにちは、制作部 フロントエンドエンジニアの武田です。 入社して5ヶ月経ちました。 ECMAScript の推し proposal は Cancellation API です。 今回は開発には切っても切れない Babel 、そのプリセットである babel-preset-env についてお話します。 このプリセットは Browserslist 1 の記述で compat table 2 を利用し、指定された環境にあったトランスパイルができるプリセットです。 使い方についての記事はすでに多くありますので今回は丁寧に触れません。 babel-preset-env を試す – アカベコマイリ最新版で学ぶwebpack 3入門 - ICS MEDIAピンと来ない方は、JavaScript をとりまくビルド環境のスケーリングに寄与しそう、と大きく理解していただいてよいです。 対象となりそうな人Ba
This in JavaScript | Zell Liew
(Hey, we're having problems showing images in RSS right now, so if you want a better reading experience, consider viewing this article online [here](https://zellwk.com//blog/this. We hope to fix this soon!). Are you confused by the this keyword in JavaScript? It confuses everyone in the beginning, so don't worry about it. You're not alone. But that doesn't mean you can go on without understanding
Update on Web Cryptography
Cryptography is the cornerstone of information security, including various aspects such as data confidentiality, data integrity, authentication, and non-repudiation. These provide support for the fundamental technologies of today’s Internet like HTTPS, DNSSEC, and VPN. The WebCrypto API was created to bring these important high-level cryptography capabilities to the web. This API provides a set of
がんばらないTypeScriptのはじめ方 - 角待ちは対空
追記 2019/04/16に以下の記事が公開されました。 employment.en-japan.com gfxさんによる記事です。この記事自体2017年の若干古い記事なので、新しく読む方は最新版である上記の記事を読んだほうがいいでしょう。 このエントリは2017/07/12に行われたHatena Engineer Seminar #8 @ Tokyoの発表内容をブログ向けに書き直したものです。 事前の通知では「CoffeeScript脱出にみるTypeScript2.4時代のベストプラクティス」がタイトルだったのですが、主題を変えたためタイトルも「がんばらないTypeScriptの始め方」に変更させていただきました。CoffeeScript脱出の話は一応出てきます。 社内のTypeScript事情 その後のTypeScript 現在の様子 TypeScriptのがんばらないはじめ方
Prevent Mobile Browser From Sleeping
Web developers still have a difficult job when it comes to mobile; the web will never provide as many APIs or as much control as native mobile platforms but our users expect the same excellent experience. Creating HTML5 games and media-heavy apps for the web can be really difficult, as you really have to pay attention to performance the the rest of the little things that native platforms provide.
Let's Dev: A Package Manager
For Yarn 2+ docs and migration guide, see yarnpkg.com. Posted Jul 11, 2017 by Maël Nison Hello everyone! Today, we’re gonna write a new package manager, even better than Yarn! Ok, maybe not, but at least we’re gonna have some fun, learn how package managers work, and think about what could come next on Yarn. The devil is in the details This article omits small details and environment quirks, and f
Getting started with PreactJS — A Step By Step Guide
PreactJS is a fast 3kB alternative to React with the same ES6 APIFirst, some background…PreactJS is developed by Jason Miller — one of my programming heroes. The framework was developed with a goal of providing high performance, memory efficiency and close compatibility with React API with an aim to keep the footprint as small as possible i.e 3kb. Preact is increasingly getting adopted in the comm
una.im | Locally Scoped CSS Variables: What, How, and Why
Locally Scoped CSS Variables: What, How, and Why Published on June 5, 2017 CSS Custom Properties (also popularly called CSS Variables) are here! This is really exciting because we finally have true variables in CSS! What do I mean by true variables? I mean variables that can be updated and altered dynamically in the file. While we had “variables” with pre/post-processors (like Sass and PostCSS), t
Codemods: A Quick and Easy Way to Automate Code Refactoring — SitePoint
Stay Relevant and Grow Your Career in TechPremium ResultsPublish articles on SitePointDaily curated jobsLearning PathsDiscounts to dev toolsStart Free Trial7 Day Free Trial. Cancel Anytime. Key Takeaways Codemods, developed by Facebook, offer a powerful solution for automating large-scale refactoring tasks, enabling developers to efficiently update codebases to align with new JavaScript standards
Aligned input events | Blog | Chrome for Developers
TL;DR Chrome 60 reduces jank by lowering event frequency, thereby improving the consistency of frame timing. The getCoalescedEvents() method, introduced in Chrome 58 provides the same wealth of event information you've had all along. Providing a smooth user experience is important for the web. The time between receiving an input event and when the visuals actually update is important and generally
Choo, architecture & performance
Almost every Choo release so far has managed to include more features, and reduce the size on disk. In the upcoming v6 release we’re now sitting at 3.8Kb. People often ask how it’s possible to pack a “batteries included” browser framework into something that’s about an order of magnitude smaller than conventional options. This post is intended to break down the bits that make up Choo, and explain
Home — Marius Schulz
How to configure familiar keyboard shortcuts for common navigation and edit actions in the iTerm2 command prompt, such as jumping to the start or end of a word or line. TypeScript 3.7 implemented support for assertion functions in the type system. An assertion function is a function that throws an error if something unexpected happened. Using assertion signatures, we can tell TypeScript that a fun
Into the Great Unknown — Migrating from Mocha to Jest
A Tale of Adventure, Ambition and JavaScript Unit Tests Facebook’s unit test framework Jest has a lot going for it: it makes writing tests for React components a breeze with its snapshot testing feature, it runs tests very quickly through parallel test execution and it is very easy to set up. Inspired by Chris Pojer’s talk at JSConf.eu 2017, I decided to overcome my unease about relying on yet ano
Using Fetch | CSS-Tricks
Support for Fetch is pretty good! All major browsers (with the exception of Opera Mini and old IE) support it natively, which means you can safely use it in your projects. If you need support anywhere it isn’t natively supported, you can always depend on this handy polyfill. Getting data with Fetch Getting data with Fetch is easy. You just need to provide Fetch with the resource you’re trying to f
All About Recursion, PTC, TCO and STC in JavaScript
All About Recursion, PTC, TCO and STC in JavaScript 8th of May, 2017 — Lucas Fernandes da Costa at Florianópolis, Brazil🇧🇷 Recently everyone seems to be really excited about functional programming and its concepts. However, many people don't talk about recursion and, especially, about proper tail calls, which is really important when it comes to writing clean and concise code without exploding t
A Worker-Owned Tech Consultancy - Bocoup
The Many Faces of Functions in JavaScriptPosted by Leo Balter If you’ve had any contact with JavaScript code, you’re probably very familiar with how to define and call functions, but are you aware of of how many different ways you can define a function? This is a common challenge of writing and maintaining tests in Test262—especially when a new feature comes into contact with any existing function
An open-source web platform for the new President of France (Symfony Blog)
Services Upsun for Symfony Best platform to deploy Symfony apps SymfonyInsight Automatic quality checks for your apps Symfony Certification Prove your knowledge and boost your career SensioLabs Professional services to help you with Symfony Blackfire Profile and monitor performance of your apps This Case Study is a guest post written by Titouan Galopin, lead engineer and product lead at EnMarche p
JavaScript のもう一つの「関数名」 —— name プロパティ - Qiita
「関数名」と name プロパティ JavaScript において「関数名」あるいは「メソッド名」というと何を指すでしょうか。 関数オブジェクトを参照している変数名やプロパティ名を指すことが多いと思います。 しかし、もう一つ「関数の名前」と言える物として、関数オブジェクトの name プロパティがあります。 これは関数オブジェクトの生成時に決定される、文字列のプロパティです。 function foo() { // do something } let bar = foo let baz = foo let qux = [foo, foo] console.log( foo.name ) // 出力 -> "foo" console.log( bar.name ) // 出力 -> "foo" console.log( baz.name ) // 出力 -> "foo" console.l
An Overview of JavaScript Testing in 2020
(Updated on: 21.11.2021) This guide is intended to catch you up with the most important reasoning, terms, tools, and approaches to JavaScript testing for the year 2022. It combines information from the best articles recently released (they are referenced at the bottom) and adds from my own experience. It’s a little long but whoever reads and understands this guide, can safely assume they know the
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