r/javascript • u/Martinsos • 7d ago
r/javascript • u/Vinserello • 6d ago
3 drop-in JS widgets (forecast, dashboard, anomaly detection) that run 100% in the browser via WASM
github.comSpent the last months building
@datastripes/forecast
@datastripes/dashboard
@datastripes/anomaly
These are framework-agnostic npm packages (React, Vue, Angular, or a plain custom element) that add time-series forecasting, an editable dashboard builder, and anomaly detection to any frontend app.
Everything runs client-side via WebAssembly, so no user data ever hits a server except a license check without a backend to deploy, no Python microservice.
Would genuinely love feedback from anyone who's had to build this kind of feature in-house.
https://datastripes.com/forecast-widget/
r/javascript • u/gosshedd • 7d ago
I made a practice tool for JavaScript that requires you to type all answers
nadir.devr/javascript • u/Professional-Pear351 • 7d ago
langgraph-harness: a LangGraph.js agent system for GitLab, written in TypeScript
github.comI’m most comfortable in JS/TS, and I wanted to learn LangGraph.js properly, so I wanted to build in that. When I looked for a production-grade example, the closest thing I found was Deep Agents, but that’s a library for building agents, not a full system. The complete systems I saw were mostly Python, like Open SWE. So I built my own.
It reviews GitLab merge requests and resolves issues. It’s been running in production for a few months, 1,000+ reviews so far. A webhook drops each review into a BullMQ queue, a LangGraph.js agent does the work with GitLab tools over MCP, runs are checkpointed in Postgres, and there’s a React admin UI where I can watch runs live. I also had to add guardrails to stop the agent repeating tool calls or quitting before it’s done.
MIT, all TypeScript.
r/javascript • u/crazy-dev-42 • 7d ago
Knitting — a shared-memory concurrency runtime for JavaScript
js.knitting.runI've been working on Knitting, a JavaScript worker runtime using shared memory for communication and work stealing for scheduling.
Some results from the published benchmarks:
- 8.9× faster empty-call round trips than
postMessageon Node.js (4.4× on Bun, 4.3× on Deno). - 86% lower p99 latency in a Hono server test: 16.93 → 2.31 ms at 6,000 req/s.
- Nearly identical CPU per request in that test: 180 → 183 µs.
- 3.5× CPU-heavy throughput on Node.js with four extra workers.
I've been working on this for more than a year, so there are a lot of things to showcase, but knitting was designed to offload work from servers.
Features:
- Typed worker calls and specialized payload types
- Shared-memory transport and zero-copy buffers
- Work stealing and automatic load balancing
- Timeouts and cancellation with real signals
- Precompiled workers and process isolation
- Process workers
- Permission (when available)
- And more ...
Docs · Benchmarks · GitHub
r/javascript • u/vmdarji85 • 7d ago
I am working on a playwright with JS/TS. I want to prepare for the upcoming SDET interview including coding practice on JavaScript and TypeScript. Can someone guide me from where and what I should learn/prepare?
r/javascript • u/subredditsummarybot • 9d ago
Subreddit Stats Your /r/javascript recap for the week of October 12 - October 18, 2026
Monday, October 12 - Sunday, October 18, 2026
Top Posts
| score | comments | title & link |
|---|---|---|
| 22 | 6 comments | Making the web 3D - Extensible Scalable 3D File Format |
| 15 | 4 comments | Chartist v2: we brought the 10-year-old SVG charting library back on track (now with SSR and terminal charts) |
| 11 | 1 comments | eval() in a straitjacket: sandboxing JavaScript under CSP |
| 11 | 25 comments | [AskJS] [AskJS] How do you host your smaller Node.js apps? Building something and want opinions |
| 11 | 2 comments | How we made JavaScript analyzer understand control flow |
| 10 | 2 comments | [Subreddit Stats] Your /r/javascript recap for the week of October 05 - October 11, 2026 |
| 7 | 0 comments | Mutative v2 - better immutability and faster immutable updates |
| 6 | 6 comments | [AskJS] [AskJS] Building a clone like Spline |
| 5 | 0 comments | How to Implement a Distributed Recovery Ramp in JavaScript |
| 5 | 5 comments | [Showoff Saturday] Showoff Saturday (October 17, 2026) |
Most Commented Posts
| score | comments | title & link |
|---|---|---|
| 0 | 23 comments | I embedded Node.js in a native program to render JSX without a browser and without React |
| 0 | 11 comments | I built a free anime “where to watch” site with 45k static pages, here’s how it keeps its data fresh without a backend |
| 0 | 10 comments | [AskJS] [AskJS] I compare full move logs instead of a hash to prove two bots played the same games. Overkill? |
| 2 | 7 comments | I built a real-time multiplayer drawing game (InkLink) using React and modern web tech—here is how it works and what I learned |
| 4 | 6 comments | Mimic - a browser-based dev environment that runs Node.js |
Top Ask JS
| score | comments | title & link |
|---|---|---|
| 3 | 4 comments | [AskJS] [AskJS] What are your opinions on express-zod-api? |
Top Showoffs
Top Comments
r/javascript • u/moving808s • 9d ago
three-nebula v13.3.0 (Helix) released, deterministic particle behaviors with seeded noise and JSON round-tripping
github.comthree-nebula is a magical 3D particle engine for the web. I maintain it, and v13.3.0 (Helix) is the first of a few releases working back toward the library's original design goals. This one is additive and backward-compatible, so it is a safe bump.
The engineering theme this release is determinism. Two new behaviors and four new emission zones all produce the same output given the same seed, which matters a lot when you want reproducible scenes, snapshot testing, or editor previews that do not drift between runs.
The first behavior, Vortex, applies a tangential swirl around an axis with optional inward or outward pull and radial falloff. It acts directly on particle velocity rather than going through the Force path, which means it sidesteps the internal Force x100 scaling quirk and stays predictable. The second, CurlNoise, drives particles with the curl of a Perlin field. The curl of a vector field is divergence-free, so particles roil without clumping into sinks. The noise is seeded through mulberry32 rather than Math.random, so nothing in the pipeline reaches for global nondeterministic state.
The four new zones (RingZone, DiscZone, CylinderZone, ConeZone) sample uniformly and are axis-aligned to +Y. Ring and Disc are planar emission zones, while Cone and Cylinder are solid and work as true 3D CrossZone boundaries. All five new types round-trip through System.fromJSON, and the debug renderer draws wireframes for the new zones, so serialization and tooling stay in step with the runtime.
Release notes and full changelog are here: https://github.com/creativelifeform/three-nebula/releases/tag/v13.3.0
I would be curious what people think about the seeded-RNG approach for a library like this. Threading an explicit seed everywhere instead of Math.random adds a little API surface, but it is what makes the JSON round-trip and snapshot tests reliable. Have you handled determinism differently in your own simulation or animation code?
r/javascript • u/OtherwisePush6424 • 9d ago
How to Implement a Distributed Recovery Ramp in JavaScript
blog.gaborkoos.comCircuit breakers are good at stopping traffic and bad at resuming it. When a breaker closes, every replica goes back to the constructor limit at the same moment, so a dependency that just answered a few probes receives its full load again.
I've been adding a recovery ramp to Caracal, my TypeScript resilience library, on top of its distributed bulkhead, rate limiter and circuit breaker.
This is the sixth article in a series on distributed resilience. Feedback welcome, particularly if you have run slow start or ramp-up in production.
r/javascript • u/FriendshipCreepy8045 • 9d ago
Some things I've built, some things I've learned.
blog.vedasdixit.comAs a software engineer I always love creating unique and cool designs and animations on the web, and I also wanted a blogging website for myself.
Recently I made my personal blog and wanted something hand-drawn on it so I sketched some flowers on my iPad and exported them as SVGs, then I wrote a script that cuts each drawing into its flower head, buds and leaves (the drawn stems get thrown away), and the site grows long curvy stems in code, hangs the leaves and buds along them and puts the flower at the tip.
Every stroke is drawn in gradually with CSS. After that, in React, I hooked that progress to the scroll while the photo stays pinned. All this just to create the scroll animation on the page above.
tbh idk how good it looks, but I wanted to do something creative for my first blog website.
Any feedback will be highly appreciated!
r/javascript • u/Ok_Chance_9305 • 10d ago
AskJS [AskJS] Building a clone like Spline
Can any one tell me what do they miss or i should implement extra to solve the problem of 3d design and building with easy integartion of 3d tech and design i choose Next js for fast And dynamic reload and three js for 3d designing and gizmo and other stuff comes from react-three-fibre/drei and library i m trying to build ui similar to spline so comment down for a feature You were hopping in this app
I will soon deploy
r/javascript • u/shmurrie • 10d ago
eval() in a straitjacket: sandboxing JavaScript under CSP
stringutilitybelt.comr/javascript • u/HighAtNight • 9d ago
contextjsx - Composable JSX for prompts. Type-safe tools and skills, defined once and exportable as CLI help, docs, SKILL.md and an MCP server.
github.comIt's a tiny library for how I love to do these tings. Lemme know what you think!
r/javascript • u/AutoModerator • 11d ago
Showoff Saturday Showoff Saturday (October 17, 2026)
Did you find or create something cool this week in javascript?
Show us here!
r/javascript • u/Fair-Process-7291 • 10d ago
AskJS [AskJS] I compare full move logs instead of a hash to prove two bots played the same games. Overkill?
Bots in my game sim (TypeScript, built with Cline) kept printing identical rows. Equal averages can be a coincidence, so I didn't want the lab saying "these bots played the same" unless they actually did. So every move gets logged as a short string: `B:ticker:cents` for a buy, `S:holdingId` for a sell, `K` for a skip. Moves are joined with commas, all 1,000 games with newlines, and two bots only match if the whole strings are equal.
I skipped hashing mostly because the result ends up in posts and I didn't want a collision to be possible at all. Yeah, SHA-256 collisions aren't a real risk. The better reason is probably debugging. Factorio's old desync post does a CRC every tick so they know the first tick where two runs split. A hash just tells you "different."
Would you have hashed it? And if you keep logs, do you store the whole thing or just enough to find the first diff?
r/javascript • u/Busy-Speech-3164 • 12d ago
Chartist v2: we brought the 10-year-old SVG charting library back on track (now with SSR and terminal charts)
chartist.devr/javascript • u/Willing-Novel6708 • 10d ago
Why do Next.js boilerplates force you to delete half their code? Built 4 isolated kits instead.
mansastack.bzdevelopments.mer/javascript • u/ty_namo • 11d ago
AskJS [AskJS] What are your opinions on express-zod-api?
Context: I'm coming from Python with FastAPI and want to try build a similar app using express, but the thing i'm most lazy about is definitely configuring swagger, compared to the built-in swagger integration that fastapi provides. apparently express-zod-api tries to bridge that gap, but i don't know how good is it?
r/javascript • u/Appropriate-Letter87 • 12d ago
I built a free anime “where to watch” site with 45k static pages, here’s how it keeps its data fresh without a backend
tsuzuki-anime.github.iohey! tsuzuki is a free site that tells you which legal platform streams an anime in your country
source code: https://github.com/tsuzuki-anime/tsuzuki-anime.github.io
no server, no database, just node scripts + github actions + github pages. a few things i figured out along the way:
- weekly full fetch, daily light fetch: the full catalog (18k anime) is only rebuilt on sundays. other days the script reuses the published json and only refreshes airing shows, which cut api calls by ~90%
- safety guards: if the api returns way less data than what’s live (it happened), the build refuses to publish, so the site never goes half empty
- wikidata as a second source: one SPARQL query adds french titles and extra streaming links that the main api didn’t have
- watch order guides: built automatically by walking the prequel/sequel graph of each franchise
everything is free, no ads, no account. happy to answer questions about the setup!
r/javascript • u/kierzniak • 13d ago
AskJS [AskJS] How do you host your smaller Node.js apps? Building something and want opinions
I'm building a host for JavaScript apps and I'd like opinions from people who ship Node.js.
The idea is shared hosting for JS. Your app runs as plain Node.js, with its database, files and cron jobs side by side in one region. When nobody visits, the app is suspended to disk and holds no memory, and the next request usually wakes it in about 0.2 seconds. That's how many apps can share one server, the way PHP hosting always worked.
The trade-off is that your code doesn't run at the edge. My bet is that for most apps, a database next to the code matters more than a server near every visitor.
A few questions for you
- How do you host side projects and smaller production apps today?
- Does edge compute actually help your apps, or is the database round trip the real cost?
- Would a 0.2 s wake-up after idle be fine for your apps?
r/javascript • u/archieofficial • 13d ago
Mimic - a browser-based dev environment that runs Node.js
github.comr/javascript • u/thereactnativerewind • 13d ago
The Great Graphite Migration, Derek Joins Fat Fighters, and a Leaderboard for Your Dependency Tree
thereactnativerewind.comHey Community,
OpenGL has been driven out of the herd. William Candillon released React Native Skia 3.0, which swaps the old Ganesh backend for Graphite running on WebGPU via Dawn, with Metal on iOS and Vulkan on Android, multithreaded recording by default, and zero-copy textures shared with React Native WebGPU. The package also leaves u/shopify behind and is now published as react-native-skia.
We also look at babel-plugin-react-native-direct-imports by Davyd NRB, which rewrites react-native barrel imports into direct requires so one View no longer drags in the whole framework, taking a test bundle from 711 KB to 10 KB. Plus, React Native 0.88 rc.4, Tamagui 3.0 with a C++ native runtime, and munim-maps putting 3D cars on Apple Maps.
r/javascript • u/gabrielmfern • 13d ago
I embedded Node.js in a native program to render JSX without a browser and without React
forbear.devI'm building a UI library in Jai, and this is an experiment with rendering its UI from JavaScript. Node.js is embedded into the program, so the native side reads the JSX objects straight out of V8, with no IPC and no JSON. It then lays out and draws the whole UI from scratch every frame, at 240 Hz on my Linux computer.
Async isn't supported on it yet, and I've only started implementing some event handling. Here's the source code: https://github.com/gabrielmfern/forbear
Has anyone built something like this? If so, I'd love some advice on how I can reduce the C++ layer and have more of it in Jai instead.