WebSockets vs Server-Sent-Events vs Long-Polling vs WebRTC vs WebTransport For modern real-time web applications, the ability to send events from the server to the client is indispensable. This necessity has led to the development of several methods over the years, each with its own set of advantages and drawbacks. Initially, long-polling was the only option available. It was then succeeded by Web
Node.js has undergone a remarkable transformation since its early days. If you’ve been writing Node.js for several years, you’ve likely witnessed this evolution firsthand—from the callback-heavy, CommonJS-dominated landscape to today’s clean, standards-based development experience. The changes aren’t just cosmetic; they represent a fundamental shift in how we approach server-side JavaScript develo
BigQueryのアンチパターン認識ツールで独自のSQLリンターを開発しました - ZOZO TECH BLOG
こんにちは、株式会社ZOZOで25卒の内定者アルバイトをしている村井です。この記事では業務で取り組んでいる、BigQueryで使うSQLのリンターの作成方法について紹介します。 目次 目次 課題と解決策 課題 解決策 BigQueryのアンチパターン認識ツール ミニマムな使い方 日本語がSQL内に含まれている際の問題 アンチパターンを定義する リンターとしてBigQueryのアンチパターン認識ツールを使用する際に生じる課題と解決策 構成 APIサーバ化 Chrome拡張 動作例 まとめ 課題と解決策 課題 社内では様々なチームがSQLを書いており、動作はするものの良くない書き方をしている場合があります。そういった構文を検知して、前もって修正する必要があります。 解決策 BigQueryのコンソールで入力されたSQLの不正構文を検知、修正案を提示できるようにしました。 BigQueryのアン
Patterns for Reactivity with Modern Vanilla JavaScript – Frontend Masters Blog
“Reactivity” is how systems react to changes in data. There are many types of reactivity, but for this article, reactivity is when data changes, you do things. Reactivity Patterns are Core to Web Development We handle a lot with JavaScript in websites and web apps since the browser is an entirely asynchronous environment. We must respond to user inputs, communicate with servers, log, perform, etc.
Today we’re excited to announce the release of TypeScript 5.2! If you’re not familiar with TypeScript, it’s a language that builds on top of JavaScript by making it possible to declare and describe types. Writing types in our code allows us to explain intent and have other tools check our code to catch mistakes like typos, issues with null and undefined, and more. Types also power TypeScript’s edi
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
Node.js compatibility for Cloudflare Workers – starting with Async Context Tracking, EventEmitter, Buffer, assert, and util
Node.js compatibility for Cloudflare Workers – starting with Async Context Tracking, EventEmitter, Buffer, assert, and util2023-03-23 Over the coming months, Cloudflare Workers will start to roll out built-in compatibility with Node.js core APIs as part of an effort to support increased compatibility across JavaScript runtimes. We are happy to announce today that the first of these Node.js APIs –
Today we’re excited to announce our Release Candidate of TypeScript 5.2! Between now and the stable release of TypeScript 5.2, we expect no further changes apart from critical bug fixes. To get started using the RC, you can get it through NuGet, or through npm with the following command: npm install -D typescript@rc Here’s a quick list of what’s new in TypeScript 5.2! using Declarations and Explic
In the early 90’s, being a frisian kid obsessed with computers there weren’t a ton of ways to get access to new software or learn more about computers. The two main ways were exchanging 3.5” diskettes with friends, or go to the library. One book I remember more than others was “Windows for Kinderen” (“Windows for Kids”) by Addo Stuur. I must have been around 10 years old and was obsessed by this b
Syntax Highlighting in Hand-Coded Websites The problem I have been trying to identify practical reasons why hand-coding websites with HTML and CSS is so hard (by hand-coding, I mean not relying on frameworks, generators or 3rd party scripts that modify the DOM). Let's say, I want to make a blog. What are the actual things that prevent me from making—and maintaining—it by hand? What would it take t
Wasm core dumps and debugging Rust in Cloudflare Workers
Wasm core dumps and debugging Rust in Cloudflare Workers2023-08-14 A clear sign of maturing for any new programming language or environment is how easy and efficient debugging them is. Programming, like any other complex task, involves various challenges and potential pitfalls. Logic errors, off-by-ones, null pointer dereferences, and memory leaks are some examples of things that can make software
Comprehensive guide to JavaScript performance analysis using Chrome DevTools
Comprehensive guide to JavaScript performance analysis using Chrome DevTools Let's see how to navigate the Chrome Devtools Performance tab to effectively analyse and improve the performance of your JavaScript while avoiding common errors. Our use case will be improving the rendering FPS of a real-world canvas library. A few weeks ago a colleague of mine and I were looking at the canvas engine comp
Scheme in the browser: A Hoot of a tale -- Spritely Institute
Scheme in the browser: A Hoot of a taleDave Thompson — October 10, 2023 Hey there, it’s been a while! We’re back to share some more exciting news about Guile Hoot, a WebAssembly toolchain and Scheme→WASM compiler. In our last post we demonstrated that the Guile Hoot toolchain can be used to assemble programs written in WebAssembly Text (WAT) format, which allowed us to develop for the WASM-4 fanta
AbortController is your friend
AbortController is your friend One of my favorite new features of JS is the humble AbortController, and its AbortSignal. It enables some new development patterns, which I'll cover below, but first: the canonical demo. It's to use AbortController to provide a fetch() you can abort early: Sorry, your browser doesn't support an inline demo. And here's a simplified version of the demo's code: fetchBut
React Native 0.76 with the New Architecture by default is now available on npm! In the 0.76 release blog post, we shared a list of significant changes included in this version. In this post, we provide an overview of the New Architecture and how it shapes the future of React Native. The New Architecture adds full support for modern React features, including Suspense, Transitions, automatic batchin
DisclaimerAll projects mentioned in this blog post have been contacted, and I confirmed that the behavior described in this article is either working as intended, already fixed, or will not be fixed. TL;DRThe browser loads elements in the HTML from top to bottom, and some JavaScript libraries retrieve data or attributes from the DOM after the page has been completely loaded. Because of how the con
Today we are excited to announce the availability of TypeScript 5.2 Beta. To get started using the beta, you can get it through NuGet, or through npm with the following command: npm install -D typescript@beta Here’s a quick list of what’s new in TypeScript 5.2! using Declarations and Explicit Resource Management Decorator Metadata Named and Anonymous Tuple Elements Easier Method Usage for Unions o
Err... thanks for the technical explanation. But what does this actually mean in real life? Which setting should you use? Does it even matter? And if it does, why don't those clever browser engineers just set it to the best setting? Well recently I ranted on Twitter about this (as I am often want to do!) in a long thread that really should have been a blog post. So here is that blog post. Some mis
JestとReact Testing Libraryで学ぶReactアプリのテスト入門：基礎から応用まで - deve.K's Programming Primer - プログラミング初心者のための入門ブログ
今回は、JavaScriptのテストフレームワークとコンポーネントをテストするためのReactユーティリティの組み合わせとして人気の高い、JestとReact Testing Libraryを使ってReactアプリケーションをテストする方法について説明します。 テストとは ユニットテストと結合テスト テストカバレッジで省略すべきもの Jestとは？ React Testing Library(RTL)とは？ ユニットテストの構築 結合テストの構築 JestとRTLのモック スナップショットのテスト 最後に テストとは テストは、アプリケーションとやり取りして、そのすべての機能と機能が意図したとおりに動作することを確認する行為またはプロセスです。 また一般に、「手動テスト」と「自動テスト」の2種類のテストがあります。 ・ 手動テスト： 手動テストは、テストを人間が手動で実行する手法です。 手
The web dev community has spent the past few weeks buzzing about signals, a reactive programming pattern that enables very efficient UI updates. Devon Govett wrote a thought-provoking Twitter thread about signals and mutable state Devon Govett on X Easy to forget, but the debate about signals is the same one we had about 2-way data binding vs unidirectional data flow 10 years ago. Signals are muta
Ezno in '23
It's been a minute since the previous announcement so I thought would give some updates and share some upcoming problems. This follows the initial announcement and includes some smaller things I shared on Twitter since the announcement post. Never heard of Ezno? It is a parser, partial executor, optimizer and type checker for JavaScript! Read the initial announcement. New changes Classes, getters
Introducing TanStack Start Middleware – Frontend Masters Blog
TanStack Start is one of the most exciting full-stack web development frameworks I’ve seen. I’ve written about it before. In essence, TanStack Start takes TanStack Router, a superb, strongly-typed client-side JavaScript framework, and adds server-side support. This serves two purposes: it gives you a place to execute server-side code, like database access; and it enables server-side rendering, or
Browser-Powered Desync Attacks: A New Frontier in HTTP Request Smuggling
This request triggered an extremely suspicious intermittent 400 Bad Request response from various websites that were running AWS Application Load Balancer (ALB) as their front-end. Investigation revealed that ALB was mysteriously adding a 'Transfer-Encoding: chunked' header while downgrading the request to HTTP/1.1 for forwarding to the back-end, without making any alterations to the message body:
An overview of Node.js: architecture, APIs, event loop, concurrency
Warning: This blog post is outdated. Instead, read chapter “An overview of Node.js: architecture, APIs, event loop, concurrency” in “Shell scripting with Node.js”. This blog post gives an overview of how Node.js works: What its architecture looks like. How its APIs are structured. A few highlights of its global variables and built-in modules. How it runs JavaScript in a single thread via an event
With software development, we are often presented with alternative choices for libraries and tools that appear to accomplish the same sort of things. Each one will advertise its key advantages, and we attempt to weigh the pros and cons. Sometimes, the differentiators have less to do with what we are accomplishing and everything with how we accomplish it. In those cases, it isn't always as clear wh
The seventh way to call a JavaScript function without parentheses
The seventh way to call a JavaScript function without parentheses Published: 12 September 2022 at 13:00 UTC Updated: 18 September 2022 at 17:20 UTC I thought I knew all the ways to call functions without parentheses: alert`1337` throw onerror=alert,1337 Function`x${'alert\x281337\x29'}x``` 'alert\x281337\x29'instanceof{[Symbol['hasInstance']]:eval} valueOf=alert;window+'' x=new DOMMatrix;matrix=al
Exploring The Potential Of Web Workers For Multithreading On The Web — Smashing Magazine
Multithreading is an important technique used in modern software development to enhance the performance and responsiveness of applications. However, it’s not a common practice on the web due to the single-threaded nature of JavaScript. To overcome this limitation, Web Workers were introduced as a way to enable this technique in web applications. In this article, Sarah Oke Okolo explores the import
先ほど、AWS re:Invent 2025 の Opening Keynote with Matt Garman (KEY001) にて、AWS Lambda の新機能である Lambda durable functions が発表されました！ What's new 公式ドキュメント 一言で言えば、Lambda の実行の途中にチェックポイントを設置でき、設置したチェックポイントからの再開を行うことで、長時間実行する必要のあるワークフローやポーリングのような処理を、サーバーレスの体系で実現する新機能です。 リリースの 2025/12/3 時点で、us-east-2 でサポートされています。 この記事は Serverless アドベントカレンダー 3日目の記事です。 tl;dr Lambda の状態管理と長時間実行を簡単にする新機能 複数ステップの処理を単一の関数で書ける 実行途中で待機や一
Stripeを導入するためにStripeのドキュメントを確認したけれどどこから何を始めていいのかわからなかったという人を対象にStripeを導入するために必要な組み込み方法を説明しています。Stripeでオンライン決済といってもプログラミングの得意な人向けの方法から全くプラグラミングがわからない人でもお手軽に導入できる方法まで幅広い方法が提供されています。その上、プログラミングを使って組み込む方法も一つではなくシチュエーションによって利用するAPIが異なるため混乱する人も多いと思いますのでぜひ参考にしてみてください。Stripeの料金体系や成り立ちなどの説明はなく組み込み方法を中心にStripeの基本的な仕組みを理解したい技術者向けの内容になっています。 アカウントの作成 Stripeを利用するためにはStripeのアカウントを作成する必要があります。テスト目的で利用する場合は名前、メール
Photo by Clément Hélardot on UnsplashWhen we begin a project, we tend to focus on things like scalability, usability, availability, security, and others. But, as the application grows, we may observe a decline in its speed and performance. It is often only at this point that we recognize the need for optimization. In this article, we will present some of the most common techniques for optimizing c
Here is a list of common JavaScript interview questions with detailed answers to help you prepare for the interview as a JavaScript developer. JavaScript continues to be a cornerstone of web development, powering dynamic and interactive experiences across the web. As the language evolves, so does the complexity and scope of interview questions for JavaScript developers. Whether you’re a fresher de
Scheduling Internals
A sneak peek to what's coming! I remember when I first learned that you can write a server handling millions of clients running on just a single thread, my mind was simply blown away 🤯 I used Node.js while knowing it is single threaded, I used async / await in Python, and I used threads, but never asked myself "How is any of this possible?". This post is written to spread the genius of concurrenc
Python behind the scenes #12: how async/await works in Python
Mark functions as async. Call them with await. All of a sudden, your program becomes asynchronous – it can do useful things while it waits for other things, such as I/O operations, to complete. Code written in the async/await style looks like regular synchronous code but works very differently. To understand how it works, one should be familiar with many non-trivial concepts including concurrency,
JavaScript is a single-threaded language (single call stack). So, how can it be asynchronous? Are you also having the same thoughts? This article will explain how we can do asynchronous programming in JavaScript. However, before getting into that, let us first understand what asynchronous programming is and the difference between synchronous and asynchronous coding. What is Asynchronous Programmin
Thanks to my sponsors: Mike English, Anson VanDoren, Malik Bougacha, Antoine Rouaze, Brooke Tilley, Em Sharnoff, kuerbsikakteen, Nicolas Riebesel, Matt Jadczak, Bob Ippolito, Corey Alexander, Simon Menke, Carson Page, Jelle Besseling, Taneli Kaivola, you got maiL, Sean Bryant, Manuel Hutter, Ben Mitchell, Matt Heise and 253 more I still get excited about programming languages. But these days, it’s
Using the Popover API for HTML Tooltips – Frontend Masters Blog
Can it be done? This plucky front-end developer intends to find out. We looked at the Popover API and how it’s made it’s way across all browsers already just last week. One of the things I should have done is looked at the accessibility considerations more closely. Thanks to Melanie Sumner there is a great explainer with demos. I tried to adhere to the points made in there the best I could while m
Update 1.88.1: The update addresses these issues. Downloads: Windows: x64 Arm64 | Mac: Universal Intel silicon | Linux: deb rpm tarball Arm snap Welcome to the March 2024 release of Visual Studio Code. There are many updates in this version that we hope you'll like, some of the key highlights include: Apply custom editor labels - Distinguish between editors with same file names. Locked scrolling -
Svelte 5 is not Javascript
For the last couple of weeks, I've been dealing with the fallout of upgrading a web application to Svelte 5. Complaints about framework churn and migration annoyances aside, I've run into some interesting issues with the migration. So far, I haven't seen many other people register the same issues, so I thought it might be constructive for me to articulate them myself. I'll try not to complain too
PhobosLab
tl;dr: pl_synth is a tiny music synthesizer for C & JS and an editor (“tracker”) to create instruments and arrangements. You can try it out at phoboslab.org/synth/ The song Microscope by Ferris / Youth Uprising playing in pl_synth Sonant is a brilliant piece of software. It gives you 8 tracks, where each track has its own “instrument” (just a bunch of parameters) and a number of patterns. You fill
Frontend Memory Leaks: A 500-Repository Static Analysis and Five-Scenario Benchmark Study
Frontend Memory Leaks: A 500-Repository Static Analysis and Five-Scenario Benchmark Study You know the moment. You’re clicking through your SPA — navigating pages, filling out forms, switching tabs. Everything feels snappy. Then twenty minutes in, the UI starts stuttering. Scroll events lag. Animations drop frames. You open the Memory tab in DevTools and watch a heap line climb steadily — 200 MB,
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March 2024 (version 1.88)