Digging into explicit resource management

#​663 — November 16, 2023

Read on the Web

JavaScript Weekly

Prettier 3.1 Released — The popular opinionated code formatter has a new release including support for the new control flow syntax in Angular 17 plus a new, experimental formatting option for ternary expressions (as in x ? y : z) explained in more depth in “A curious case of the ternaries.”

Alex Rattray

🤔 With an aim to making code formatting even faster, Prettier’s co-creator has put up a $10k bounty for any Rust project that passes >95% of Prettier’s tests.

Exploring Explicit Resource Management in JS — A practical look at the idea of explicit resource management, an idea both currently at stage 3 in TC39 (and partly supported in TypeScript 5.2) that makes it easier to ‘clean up’ resources once they are no longer used or needed.

Ilia Pozdnyakov

Build Interactive, Live Video Applications with Amazon IVS — Amazon Interactive Video Service (Amazon IVS) allows developers to create dynamic video experiences, such as collaborative real-time livestreams. Check out the new ivs.rocks to find code samples, demos, and other resources. Click here to get started.

Amazon Web Services (AWS) sponsor

On HTML Web Components — “With web components, you might even say React’s component model is being ported to the browser. But it’s being done in a way that works to enhance how the web already works, not replace it”.

Jim Nielsen

A Review of Lightweight JavaScript Frameworks — This overview is targeted at Django (i.e. Python) developers but if you, too, want to avoid larger frameworks like React or Angular, you might appreciate this look at numerous alternatives from Stimulus and htmx to more oblique options like Laravel Livewire.

Michael Yin

🥳 AWS is celebrating a huge release with v6 of the AWS Amplify JavaScript library which includes full support for Next.js App Router and Server Actions.

🌎 Node.js TSC member Yagiz Nizipli is suggesting using Biome for code formatting in Node, since ESLint has deprecated its core formatting rules.

👾 The winners of React Jam, a recent React-based game development contest, have been revealed. An entry I enjoyed was useChess, a set of chess-based puzzles.

▶️ If you’ve wondered what the big deal is about Astro, James Q Quick went on the Software Engineering Daily podcast and explained Astro pretty well.

🎵 Someone’s recorded ▶️ a rap music video about TypeScript..


Node.js v21.2.0 (Current)

visx 3.5 – D3-based visualization primitives for React.

fx 31.0 – Powerful terminal JSON viewer.

Astro 3.5, Ember 5.4, and Prisma 5.6.

📄 Articles & Tutorials

67 Browser-Based Debugging Tricks — A list of useful, ‘not-obvious’ hacks to get the most out of the browser’s DevTools. Assumes a reasonable existing understanding of said tools.

Alan Norbauer

Exploring V8’s Strings: Implementation and OptimizationsNote: This is very technical and most JavaScript developers do not need to go this deep. That aside, this is a fantastic look under the covers of how the V8 engine handles strings, including the optimizations used that allow it to go toe to toe with languages like C++.

Ilia Pozdnyakov

JavaScript Scratchpad for VS Code — Quokka.js is the #1 tool for exploring/testing JavaScript with edit-continue experience to see realtime execution and runtime values.

Wallaby Team sponsor

▶  An Overview of Angular 17’s New Built-In Control FlowAngular 17 was released last week and a significant enhancement was support for a new syntax in templates that looks and feels more JavaScript-y.

Dmytro Mezhenskyi

Moving Back to React (from Preact) — Preact felt like a logical, lightweight choice to this team at one time, but they’ve switched to React for better compatibility with Next.js, among other things. Their page weight is up slightly, but they feel the tradeoff is worth it.

Ante Barić (Daily․Dev)

My Journey to 3x Faster Builds: Trimming Barrel File Imports“I maintain a small frontend application (4K LOC) which uses Vite as the compiler. The production build, using npm run build, was taking 26 secs on Github Actions. It seemed awfully slow for such a small application. I decided to investigate why.”

Ramana Venkata

Can Bun Eat Node’s ‘Lunch’? — An experiment in migrating a codebase (a restaurant voting app called Lunch) from Node over to Bun and seeing how it fares.

Jeffrey Carl Faden

Feel the Power of More Than 420,000 Teammates and Work #LikeABosch

Bosch sponsor

How to Use NPM Packages Outside of Node — Learn how to run NPM packages in ‘other places’ like serverless platforms, the browser, and beyond.

George MacKerron (Neon)

What I Learned Building an Audio Plugins System for the Web

Ben Wiley

Rust for JavaScript Developers: An Overview of Testing

Joshua Mo

🛠 Code & Tools

gsplat.js: A Gaussian Splatting Library — Gaussian splatting is an increasingly popular graphics rendering techniques where rather than render millions of tiny, textured triangles in a scene, you get a more wild paintball-like splatter fest, where each paintball creates a smooth, colorful blob instead of a rigid shape. This demo is both simple and striking.

Dylan Ebert

Reveal.js 5.0: The HTML Presentation Framework — A way to build presentations using standard Web technologies. The project’s homepage is, itself, such a presentation. v5.0 adds support for ‘scroll mode’ which essentially turns presentations into more typically scrolling Web experiences – demo.

Hakim El Hattab

🖍️ Marker.io: Collect Bug Reports With Annotations & Session Replay — Collect feedback on live websites. Get dev-friendly bug reports with screenshots, URLs, console logs & session replay.

Marker.io sponsor

Datasheet Grid: An Airtable-like React Component — If you’ve got an array of objects and you want a way for users to manipulate them, this is for you. It’s not going to replace a spreadsheet or an extensive data grid framework, but it’s a mature solution featuring smooth animations, virtualized rows/columns, keyboard navigation, and more.

Nicolas Keller

Perfect Freehand: A Library for Creating Better ‘Freehand’ Lines — You can try it out here. Makes your e-signature not look like chicken scratch! Might be useful for drawing apps.

Steve Ruiz

Wild Wild Path v5: Object Property Paths with Wildcards and Regexps — A ‘wild’ way to access properties in objects (which can be deeply nested) by way of string based queries that support wildcards and regexes. The examples help communicate the idea.


@storybook-test: More Streamlined and Powerful Storybook Testing — @storybook/test consolidates the API of @storybook/jest and @storybook/testing-library into a new, single package, powered by Vitest.

Kasper Peulen

Marked 10.0 – Markdown parser and compiler. There’s also marked-terminal 6.1 which lets you render Marked-processed Markdown on the terminal.

HumanizeDuration.js 3.31.0 – Turn milliseconds into textual durations in numerous natural languages.

actions/github-script 7.0 – Script the GitHub API in GitHub Actions.

Plasmo v0.84.0“Like Next.js for browser extensions.”

PDFKit 0.14.0 – PDF generation for Node and browser.

React Joyride 2.7 – Create guided tours in your apps.

Job Listing

Full Stack TypeScript Software Engineer – [Remote Europe]Marker.io is a visual bug-reporting tool for the web. Join our dev team and work remotely (Stack: Node.js, Vue.js & MongoDB).


“When you choose a language, you’re choosing more than a set of technical trade-offs – you’re choosing a community.”

Joshua Bloch

Bundle-time macros with Bun

#​641 — June 1, 2023

Read on the Web

JavaScript Weekly

JavaScript Macros in Bun — Not content with giving the JavaScript world a brand new bundler, Bun’s Jarred has taken it a bit further: ‘macros’ that run at bundle time with the result being directly inlined into your code. They use stage 3 annotated import statements (so may become regular JS eventually) and Jarred shows off some use cases here.

Jarred Sumner

▶  Discussing the Future of React with Two Core Team Members — As part of the celebrations around React’s 10th birthday, Vercel’s Delba de Oliveira interviewed Andrew Clark and Sebastian Markbåge of the React core team on modern topics including server components, Suspense, Actions, and the next steps React will take.

Delba de Oliveira (Vercel)

URL Validation 101 — with Snyk — Keep script injection and server side request forgery out of your JavaScript applications with Snyk.

Snyk sponsor

Aimless.js: The ‘Missing’ JavaScript Randomness Library — If you’ve been itching for functions to give you random characters, numbers from custom distributions, random sequences, random items, weighted random numbers, or more, this is for you.

Christopher Cavalea


???? Two big birthdays in the past week: Node.js turned 14 and React turned 10.

Intel and Google have been working together on the Compute Pressure API which you can use, in origin trial, in Chrome 115. It provides a way to measure the ‘computational strain’ of the system your code is running on to then adjust how your app operates accordingly.

???? Misko Hevery, creator of Angular and now Qwik, was on the Stack Overflow Podcast talking about ▶️ how he’s ‘dehydrating the Web’ in an ongoing quest for higher performance.

‘Deferring Module Evaluation’ is a TC39 proposal for basically being able to lazily load modules which are executed only upon use.

You can now use Node.js built-in modules on Deno Deploy, making it easier to run existing JS apps ‘at the edge’ on their platform.

Tom Preston-Werner, GitHub co-founder and Redwood co-creator, writes about how Redwood is going ‘all in on React Server Components’ and announces the first Redwood conference this September.

SupportsCSS: Feature Detection for Modern CSS — Inspired by Modernizr, this script expands on the capabilities of CSS’s @supports feature by adding classes to your HTML and exposing a results object so you can run custom tests live in the browser.

Stephanie Eckles

????  JSDayIE 2023: The First JavaScript Conference in Ireland Is Back! — Join us on September 26th in Dublin to experience everything the Irish JavaScript community and Ireland have to offer.

JSDayIE sponsor


Electron 25 – Now offering a Chrome-powered net.fetch (as opposed to Node’s flavor of fetch()).

Neutralinojs 4.12 – Desktop app dev framework.

Parcel 2.9

Bootstrap 5.3.0

node-oracledb 6.0

???? Articles & Tutorials

How to Draw Any Regular Shape with Just One JavaScript Function — Mozilla/MDN has a (relatively) new blog — here they share how to use JavaScript to draw any regular shape to a HTML canvas with a single function, and how to modify it to draw multiple shapes.

Ruth John

Sharing WebSocket Connections between Tabs and Windows — If your users open your app in multiple tabs or windows, being able to share a WebSocket connection could be a lot more efficient both at the client and server end. Is it possible? With SharedWorkers (supported by all major browsers, except Chrome on Android), you can.

Szymon Chmal

▶  How React Works Under The Hood: 2023 Edition — Quite a lot of depth for a mere 13-minutes. Covers React broadly, along with the pros and cons of JSX, how the virtual DOM approach works, plus React’s diffing algorithm.


Connected APM and Infrastructure Monitoring at Up to 1/3rd the Cost of Datadog

New Relic sponsor

Why Does a Farmer Emoji Have a Length of 7 in JS? — This is a nicely accessible introduction to a topic that often causes confusion. Get ready to learn a little about grapheme clusters, scalars, and code units.

Evan Hahn

The Evolution of React APIs and Code Reuse — An exploration of common React patterns, from mixins and higher-order components to render props & hooks.

Rem / Frontend Mastery

▶  ‘I Tried 8 Different Postgres ORMs’ — A modern, fast-paced, and slightly irreverent look at working with Postgres from back-end JavaScript runtimes. (9 minutes.)

Beyond Fireship

Automatically Unsubscribe from RxJS Observables in Angular Components

Rob Bell

Deploying Vanilla Node.js Apps on Fly.io

Sam Ruby (Fly)

Asynchronous JavaScript for Beginners

Daniel Agantem

???? Code & Tools

Svelvet: A Svelte Component Library for Interactive Node-Based Diagrams — You can create flow diagrams using pre-built components with seamless zooming and panning, draggable interactivity, customizable edges/nodes, etc.

Svelvet Team

Inkline 4.0: A Customizable Vue.js 3 UI/UX Library — A design system and numerous customizable components designed for mobile-first (but desktop friendly) and built with accessibility in mind.

Alex Grozav

Handsontable: Data Editor for React — There’s a lot of JS data grids out there, but none quite like Handsontable: Excel-like design, keyboard shortcuts, and React support make it the perfect data editor for web apps.

Handsontable Data Grid sponsor

JECS: An Entity Component System (ECS) for JSEntity component systems are common in game development as they provide a lot of flexibility for managing the many objects present in games.


Color Names: A Gigantic List of Handpicked Color Names — At first, I thought this was just going to be a hundred or so obvious choices like the named colors in HTML (???? rebeccapurple) but it’s actually over 30,000 colors with a fantastic array of names and uses, plus JavaScript functions to work with them.

David Aerne

fastgron: High-Performance JSON to GRON Converter‘gron’ is a transpiled form of JSON into individual assignment operations which makes it easier to grep. (fastgron is itself written in C++.)

Adam Ritter

Orama 1.0.3
↳ In-memory, typo-tolerant, text search engine.

Perspective 2.2
↳ WASM-powered high-perf data visualization component.

Javet 2.2 – Java + V8. Embed JS into Java.

OverlayScrollbars 2.2 – JS custom scrollbar plugin.

html-react-parser 4.0 – HTML to React parser.

Vuetify 3.3.2 – Vue component framework.

React Slider 10.2Demos.

???? Jobs

Find JavaScript Jobs with Hired — Hired makes job hunting easy-instead of chasing recruiters, companies approach you with salary details up front. Create a free profile now.


????‍???? Got a job listing to share? Here’s how.

????  Live-streaming from JavaScript

JSFiddle: Did You Know You Can Stream on Twitch from JavaScript? — This is an interesting experiment, but I tried it and it worked! Twitch added support for WebRTC ingestion a while ago and this CodePen example ties that together with fewer than 50 lines of JavaScript to send your preferred video source to the popular livestreaming service. It’s hardly OBS, but I imagine someone will rustle up something fancier with this approach in time.

Sean DuBois on JSFiddle

Measure Node.js server response time with N|Solid

As software developers, we constantly face new challenges in an ever-changing ecosystem. However, we must always remember the importance of addressing performance and security concerns, which remain at the top of our priority list.

To ensure that our applications based on Node.js can meet our performance and scalability needs without compromising security or incurring costly infrastructure changes, we must be aware of the importance of network optimization in Node.js.

The Impact of Latency/Ping Time on the Performance and Speed of Your Node.js Application

IMG – Ping Cats – via GIPHY

This communication, known as network ping time or latency, is a crucial factor that impacts the performance and speed of your application. Knowing how to measure network ping time between the browser and the server is essential for developers who want to optimize their applications and provide a better user experience. _Have you ever wondered how long it takes for your application to communicate with the server? _

Network Optimization in Node.js

To ensure the optimal performance and scalability of our Node.js applications, we must accurately measure our HTTP server’s connection and response time. Doing so enables us to identify and address potential bottlenecks without compromising security or incurring unnecessary infrastructure changes.

Before delving deeper into measuring connection and response time, let’s explore fundamental concepts and critical differentiators in the network landscape.

HTTP vs. WebSocket:

HTTP and WebSocket are communication protocols used in web development but serve different purposes. HTTP is a stateless protocol commonly used for client-server communication, while WebSocket enables full-duplex communication between clients and servers, allowing real-time data exchange.

Types of Connections and Versions:

When creating APIs, HTTP as a protocol and standard has different versions, such as HTTP 1.1 and 2.0. Additionally, APIs may use alternative protocols like gRPC, which offer different features and capabilities. Understanding these options empowers developers to choose the most suitable tools for their web servers.

TCP/IP Basics:

The Transmission Control Protocol (TCP) and Internet Protocol (IP) are fundamental protocols that form the backbone of computer networks. Among TCP’s critical processes is the three-way handshake, which plays a vital role in establishing a secure and dependable connection between two endpoints. This handshake ensures the orderly and reliable transmission of data. TLS/SSL encryption enhances security, adding an extra layer of protection to the communication between the client and the server.


HTTP operates over plain text, which exposes the data being transmitted to potential eavesdropping and tampering.
HTTPS, on the other hand, secures communication through the use of SSL/TLS encryption, providing confidentiality and integrity.
Understanding the trade-offs between HTTP and HTTPS is crucial to making informed data security decisions.

Building a Solid Foundation: Understanding the Three-Way Handshake for Reliable Connections

To evaluate the performance of our HTTP server, we need to differentiate between connection latency and server response time. Connection latency refers to the time it takes for the initial three-way handshake process to complete before data transmission can occur. On the other hand, server response time measures the duration from when the server receives a request to when it generates and sends the response back to the client.

The three-way handshake is a fundamental process in establishing a TCP (Transmission Control Protocol) connection between a client and a server in a network. It involves three steps, a “three-way handshake.” This handshake establishes a reliable and ordered communication channel between the two endpoints.

Here’s a breakdown of the three steps involved in the three-way handshake:

__SYN (Synchronize)__: The client initiates the connection by sending an SYN packet (synchronize) to the server. This packet contains a randomly generated sequence number to initiate the communication.
__SYN-ACK (Synchronize-Acknowledge)__: Upon receiving the SYN packet, the server acknowledges the request by sending an SYN-ACK packet back to the client. The SYN-ACK packet includes its own randomly generated sequence number and an acknowledgment number equal to the client’s sequence number plus one.
__ACK (Acknowledge)__: Finally, the client sends an ACK packet (acknowledge) to the server, confirming the receipt of the SYN-ACK packet. This packet also contains the acknowledgment number equal to the server’s sequence plus one.

Once this three-way handshake process is completed, the client and the server have agreed upon initial sequence numbers, and a reliable connection is established between them. This connection allows for data transmission with proper sequencing and error detection mechanisms, ensuring that the information sent between the client and server is reliable and accurate.

The three-way handshake is essential to establishing TCP connections and is performed before any data transmission can occur. It plays a critical role in ensuring the integrity and reliability of the communication channel, providing a solid foundation for subsequent data exchange between the client and server.

Create a self-serve diagnostic tool for a server-rendered page in Node.js.

The idea is to share an easy-to-follow recipe that will help you create your tool, so let’s start with the ingredients and end with the steps to create a self-serve diagnostic tool for a server-rendered page in Node.js.


Node.js & NPM installation – https://nodejs.org/

Fastify.js – https://www.fastify.io/


1. Setup a Node.js Project
Use NPM to create your Node project:

$ mkdir diagnostic-tool-nodejs
$ cd diagnostic-tool-nodejs
$ npm init -y

2. Install your NPM packages.
We have Fastify in our recipe, so we must install them first:

$ npm i fastify

3. Create the index.mjs
Create an index.mjs file in the project’s root directory and paste this fastify HTTP server sample code.

import Fastify from “fastify”;

const fastify = Fastify({
logger: true,

// Randomly create a timer from 100ms up to X seconds
function timer(time) {
return new Promise((resolve, reject) => {
const ms = Math.floor(Math.random() * time) + 100;
setTimeout(() => {
}, ms);

// Declare the root route and delay the response randomly
fastify.get(“/”, async function (request, reply) {
const wait = await timer(5000);
return { delayTime: wait };

// Run the server!
fastify.listen({ port: 3000 }, function (err, address) {
if (err) {

This will start the server on port 3000, which you can access by going to http://localhost:3000 in your web browser.

Integrate with N|Solid Console

Be sure you already have N|Solid installed and running on your environment; otherwise, go to https://downloads.nodesource.com and get the installer.

Also, run the console using docker as an alternative to the local installation.

docker run -d -p 6753:6753 -p 9001:9001 -p 9002:9002 -p 9003:9003 nodesource/nsolid-console:hydrogen-alpine-latest

With the application already initialized with npm, Fastify installed, and our index.js in place, we can connect our process with N|Solid

Run the HTTP server with the NSOLID RUNTIME following the instructions on the principal console page.

IMG – Connect N|Solid

In this case, we ran the process by passing the config via environment variables and running a local installation of the Nsolid console.


If you instead use our SaaS console, you need to use the NSOLID_SAAS env instead of __NSOLID_COMMAND__.

NSOLID_APPNAME=”NSOLID_RESPONSE_TIME_APP” NSOLID_COMMAND=”XYZ.prod.proxy.saas.nodesource.io:9001″ nsolid index.mjs

After completing those steps, you should be able to watch the app and process connected to the console.

IMG – Connect N|Solid Process

GIF 1 – Connect N|Solid Process

Go to the application process and add the HTTP(S) Server 99th Percentile Duration metric to see in near-real time the HTTP server latency response time and also we have the HTTP(S) Request Median Duration.

GIF 2 – Monitor Process Metrics

After this, we should be able to generate some traffic and see how the response times behave with the sample code provided, generating some response time randomness from 100ms up to 5 secs.

To generate the traffic, we can use autocannon

npx autocannon -d 120 -R 60 localhost:3000

After running autocannon for some minutes, we can see the P99 metric of the HTTP Server. The median and compare them.

IMG – http-latency-response-time-metrics

IMG – http-request-median-duration

IMG – p99-metric

To fully utilize the metrics provided by N|Solid, it is crucial to have a comprehensive understanding of their significance. Two critical metrics offered by N|Solid are the 99th Percentile and the HTTP Median metric. These metrics play a vital role in assessing the performance of Node.js applications in production environments. By getting deeper into their practical application and importance, we can unlock the actual value of these metrics in N|Solid and make informed decisions to optimize our production systems. Let’s explore this further.

The 99th Percentile metric

The 99th percentile is a statistical measure commonly used to analyze and understand response time or latency in a system.

Imagine you have a web application that handles incoming requests. To understand how fast the server responds, you measure the time it takes for each request and gather that data. You can find the 99th percentile response time by looking at the data.

For example, __the 99th percentile response time is 500 milliseconds__.
This means that only 1% of the requests took longer than 500 milliseconds to get a response. In simpler terms, 99% of the requests were handled in 500 milliseconds or less, which is fast.

It helps you identify and address any outliers or performance bottlenecks affecting a small fraction of requests but can significantly impact the user experience or system stability. Monitoring the 99th percentile response time helps you spot any slow requests or performance issues that might affect a few users but still need attention. but can have a significant impact on user experience or system stability.

The HTTP median metric

When sorted in ascending or descending order, the median represents a dataset’s middle value.

To illustrate the difference between the 99th percentile and the median, let’s consider an example. Suppose you have a dataset of response times for a web application consisting of 10 values:
[100ms, 150ms, 200ms, 250ms, __500ms__, 600ms, 700ms, 800ms, 900ms, 1000ms].

The median response time would be the middle value when the dataset is sorted, which is the 5th value, 500ms. This means that 50% of the requests had a response time faster than 500ms, and the other 50% had a response time slower than 500ms.

Connect with NodeSource

If you have any questions, please contact us at [email protected] or through this form.

Experience the Benefits of N|Solid’s Integrated Features
Sign up for a Free Trial Today

To get the best out of Node.js and experience the benefits of its integrated features, including OpenTelemetry support, SBOM integration, and machine learning capabilities. Sign up for a free trial and see how N|Solid can help you achieve your development and operations goals. #KnowyourNode