Introducing Immer: Immutability the easy way
Immutable, structurally shared data structures are a great paradigm for storing state. Especially when combined with an event-sourcing architecture. However, there is a cost to pay. In a language like JavaScript where immutability is not built into the language, producing a new state from the previous one is a boring, boiler-platy task. To prove the point: The Redux-ecosystem-links page alone list
But really, what is a JavaScript test?
But really, what is a JavaScript test?January 1st, 2018 — 9 min read Testing software. There are a ton of reasons we do it. Here are two of mine: Speeds up my workflow so I can develop software faster Helps me ensure I don't break existing code when making changes That said, I have a few questions for you (these are twitter polls): Have you ever written a JavaScript test? Have you ever used a Java
npm | the state of javascript frameworks | part 1 | introduction
The State of JavaScript Frameworks, 2017 Laurie Voss, co-founder and COO, npm, Inc. January 3rd, 2018 Part 2: The React Ecosystem » Part 1: Front-End Frameworks Update: An earlier version of this post did not include data for Angular 2.x. It has been updated to reflect this data. A disclaimer: Why popularity doesn’t matter This is an exploration of one particular metric and what it can tell us. It
Sapper: Towards the ideal web app framework
Quickstart for the impatient: the Sapper docs, and the starter template If you had to list the characteristics of the perfect Node.js web application framework, you’d probably come up with something like this: It should do server-side rendering, for fast initial loads and no caveats around SEO As a corollary, your app’s codebase should be universal — write once for server and client The client-sid
Using React Fragments for the first time - Jack Franklin
December 18, 2017Using React Fragments for the first timeReact v16 was a very exciting release for React, and included many new features. In the recent React 16.2 release, improved support for Fragments was announced, and it's this feature that I want to talk about today. The problem that fragments solveUp until React 16 each component had to return a single element: // will error class Demo exten
🐛🔨 The Contributors Guide to webpack — Part 1 🎨 🖼
The Contributors Guide to webpack is a multi-part publication series outlining the many ways that you can learn about, and contribute to the webpack open source project. You can read the first article in the series here! A(n) (eco)system overviewFirst off, if you’ve gotten this far down the article, 👏 congratulations 👏! Jumping into an unfamiliar codebase (or any for that matter) for the first t
ECMAScript 2015以降のJavaScriptの`this`を理解する
この記事はJavaScriptの入門書として書いているjs-primerのthisに関する部分をベースにしています。 またjs-primerでは書けなかった現在時点(2018年1月1日)でのブラウザの挙動についてを加えたものです。 次の場所にjs-primer版（書籍版）のthisについての解説があります。 この記事と違って実際にコードを実行しながら読めるので、学習ソースとしては書籍版を推奨します。 書籍版: 関数とthis · JavaScriptの入門書 #jsprimer また、バグ報告やPRも直接リポジトリにして問題ありません。 asciidwango/js-primer: JavaScriptの入門書 おかしい場所を選択した状態で右下にある”Bug Report”ボタンを押せば、簡単にtypoとかのバグを報告できます。(PRでも歓迎) 前置きはこの辺までで、ここから本編。 この記
EventTarget の継承可能化による EventEmitter の代替 | blog.jxck.io
Intro 念願 だった EventTarget の constructible/subclassable が DOM の仕様にマージされた。 これにより、いわゆる EventEmitter のブラウザ移植が不要になることが期待される。 Allow constructing and subclassing EventTarget Update Chrome Canary 64 で実装が確認できたため、DEMO を追加した。 EventTarget EventTarget には addEventListener, removeEventListener, dispatchEvent が定義されている。 これは、ブラウザが内部で生成する Event や、任意に生成された CustomEvent を発火/補足するために利用される。 callback = console.log.bind(cons
JavaScript のスレッド並列実行環境
これは Chromium Browser アドベントカレンダーの十日目の記事です。本記事では Chromium における JavaScript のスレッド並列実行環境について仕様・実装・API の面から包括的に紹介します。ブラウザの内部実装に興味がある人を対象に、各機能の使い方ではなく実行モデルに焦点を当てて説明しているため、難易度は高いです。使い方を知りたい人は MDN などの記事を読んでください。この記事をきっかけに実装解読に挑戦してみる人が一人でも増えると幸いです。 本記事を書くにあたり、yuki3 さんに多くのコメントをいただき、議論に付き合っていただきました。ありがとうございました。なお、文責はすべて私 (nhiroki) にあります。誤りや補足、質問などは気軽に GitHub Issue もしくは Twitter へお寄せください。 更新履歴 2018/01/15 Layout
Testing Angular 2 and Continuous Integration with Jest - Semaphore
A software developer living his passion of development since 2003. In addition to always trying to improve his skills, he’s also a proud husband and an avid gamer. Introduction Angular is one of the most popular front-end frameworks around today. Developed by Google, it provides a lot of functionality out of the box. Like its predecessor, AngularJS, it was built with testing in mind. By default, A
ES6 Modules のエラー処理を決定的(deterministic)にした話
このブラウザ バージョンのサポートは終了しました。サポートされているブラウザにアップグレードしてください。
Idiomatic Redux: Using Reselect Selectors for Encapsulation and Performance
Random musings on React, Redux, and more, by Redux maintainer Mark "acemarke" Erikson This is a post in the Idiomatic Redux series. An overview of why and how to use Reselect with React and Redux Intro 🔗︎ In a good Redux architecture, you are encouraged to keep your store state minimal, and derive data from the state as needed. As part of that process, we recommend that you use "selector function
How to use Parcel to bundle your React.js application
By Michael Ozoemena What’s Parcel? Parcel is a web application bundler which offers a blazingly fast performance utilizing multicore processing and requires zero configuration. So like Webpack? Yes, like Webpack, but lighter and with no configuration required. What this article offers. In this article, I’ll show you how you can make use of Parcel to bundle your basic React.js app built with JavaSc
Preload modules | Articles | web.dev
Published: November 23, 2024 Module-based development offers some real advantages in terms of cacheability, helping you reduce the number of bytes you need to ship to your users. The finer granularity of the code also helps with the loading story, by letting you prioritize the critical code in your application. However, module dependencies introduce a loading problem, in that the browser needs to
Patterns for designing flexible architecture in node.js (CQRS/ES/Onion)
In this post, I’ve presented a project that is using CQRS and Event Sourcing patterns. It’s organized using onion architecture and written with TypeScript. “flexible” —a free stock photo I found which makes this blog post much nicer and artistic.“flexible” how?I’m using the term flexible to promote an architecture which is able to adapt to different kind of environments. More precisely, I’m trying
The global `Reflect` object, its use cases and things to watch out for
This post is part of my Today I learned series in which I share all my web development learnings. I was reading the source code of one of Sindre Sorhus' modules today. It was the module on-change which provides the functionality of watching changes performed on Objects or Arrays. The module doesn't include much code – as it's very often the case for Sindre's modules. They serve a single purpose an
Behind the Scenes: Improving the Repository Infrastructure – React Blog
This blog site has been archived. Go to react.dev/blog to see the recent posts. As we worked on React 16, we revamped the folder structure and much of the build tooling in the React repository. Among other things, we introduced projects such as Rollup, Prettier, and Google Closure Compiler into our workflow. People often ask us questions about how we use those tools. In this post, we would like to
Arrays, symbols, and realms
On Twitter, Allen Wirfs-Brock asked folks if they knew what Array.isArray(obj) did, and the results suggested… no they don't. For what it's worth, I also got the answer wrong. Type-checking arrays Let's say we wanted to do something specific if obj is an array. JSON.stringify is an example of this, it outputs arrays differently to other objects. We could do:
document.cookieが憎い - sota1235のスライド置き場
Nihonbashi.js #3 自己紹介 @sota1235 又の名をきりんと申します メルカリでエンジニアやってます 好きな言葉: Promise.resolve() 嫌いな言葉: $.Deferred.done() document.cookieが憎い 憎いです 名作でも言及があるくらいdocument.cookieは邪悪な存在 メロスは激怒した。必ず、かのdocument.cookieを除かなければならぬと決意した。メロスにはJavaScriptがわからぬ。メロスは、フロントエンドエンジニアである。z-index: -1し、console.logして暮して来た。けれども脆弱性に対しては、人一倍に敏感であった。 なぜ憎いか そもそもCookieはHTTPレイヤーの概念です Cookieに秘密情報だのそのページに必要なものだのを突っ込むな サボらずにAjaxしてくれ データstoreし
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An Introduction to Weak Value Maps