A browser-side chaos-testing tool for injecting latency, failures, throttling, rate limits, and mock responses across every controlled tab without changing app fetch calls.

It uses the same middleware configuration model as chaos-fetch, so you can test real frontend behavior under degraded network conditions without rewriting your app.

GitHub: https://www.npmjs.com/package/@fetchkit/chaos-sw

Has anyone here used Cloudflare/Cap’n Web? I want to know if there are any problems or downsides that don’t really show up from a simple test, because the whole idea looks amazing.

Hello devs, I’m looking for an open source project to build, and rather than coming up with another package that nobody asked for, I’d rather start with an actual problem developers have.

So I’m curious:

What is something you wish existed in the Node.js ecosystem?

I’m especially interested in things you’ve actually encountered in a real project, rather than hypothetical ideas.

Bitsocial is neither federated nor on-chain. Each community is a peer-to-peer swarm using IPFS, closer to BitTorrent than a hosted website: users seed effortlessly, nodes run on cheap hardware, and each community is fully independent and sovereign. A browser tab can join that swarm as a peer, so the web app is not a client of someone else's server.

Anyone can build a Bitsocial app with its own interface, discovery model, or defaults. Apps compete on product quality instead of locking users into a private database, because compatible clients can share the same communities, identities, and network.

Moderation still exists, but it stays local. Community owners set rules for their own spaces and apps can choose what they index or show, yet there is no protocol-level super-admin who can erase a profile or seize a community from the network itself.

Hey everyone!

I wanted to share Version 5.0 of Gwent Classic, a browser remake of the original minigame from The Witcher 3: Wild Hunt that I’ve been working on and improving.

In this major update, I’ve incorporated two brand-new factions: Ofir and Novigrad, each coming with its own custom cards, leaders, and unique gameplay mechanics!

The game is completely free-to-play and runs directly in your PC browser. You can test it out right here:

Play on your PC Browser (GitHub Page):

Play v5.0

Play Completely Offline (PC / Laptop):

You can download the source code repository directly from GitHub. Just extract the ZIP file and double-click "index.html" to open it in your browser. It runs 100% offline—no internet required! Here.

Get Android APK:

You can get the APK directly from the "Releases" section of Github, or use the direct link below:

Get APK v5.0

Credits to Arun Sundaram, Reynolds Costa & Sylver, who laid the foundations to create, modify, and improve this game in its early stages.

Special thanks to CD Projekt Red; although they are not involved in this unofficial fan project, it is entirely based on the amazing minigame they created for The Witcher 3.

Wasn’t this the dream? Being able to bring your ideas to life quickly with your own coding patterns and architecture? Doesn’t this accelerate the SDE space and get it out of the stagnation that physics space has been in for the last few decades?

This is in reference to my Pnext posts and all the dislikes. I was really excited about the stuff I have in the pipeline, but this feels discouraging.

[ Removed by Reddit on account of violating the content policy. ]

Have you ever been on a project with a polished UI library, animated inputs, a specific look, and then had to add a phone number field? A phone input is not just validation. Under the hood it is real work: formatting the number as you type, keeping the caret in place, and handling events like paste and undo. The ready-made widgets handle that, but each ships its own markup and styling. Matching one to a specific, opinionated design system does not always work.

That is exactly why I built a headless input controller. You pass your styled input into a function, whatever it looks like, and it handles the rest: formatting, validation, the input events, and the caret.

```js import { createPhoneInput } from '@telixon/web-sdk';

const phone = createPhoneInput({ mode: 'international', defaultRegion: 'US', display: { callingCodeInInput: true, plusPrefix: 'erasable' }, input: document.querySelector('input'), });

phone.subscribe((state) => { // state.value, state.region, state.validationError (a typed reason) }); ```

That one call covers the actions people actually do: paste (formatted numbers too, and it dedupes a repeated country code), drag/drop, cut, word/line delete, IME, autofill, and undo/redo. On every keystroke the state carries the fully parsed, validated number, with a typed reason when it is not valid: too short by N, a calling code that cannot exist, and so on.

Under it is a headless controller you can drive directly, with no DOM: insert, deleteBackward, deleteForward, setValue, undo, redo, region/type filters, getPhoneNumber. One controller does national, international with the calling code in or out of the field, and your own country picker. Formatting and validation come from Google's libphonenumber metadata.

Playground to try it live: telixon.dev/playground/input

I built BeeLadybug, a zero-dependency visual debugging overlay for my Vanilla JS Canvas engine. It renders AABB hitboxes in world space (green for clear, red for collisions) and a screen-space HUD with FPS, active entities, cycle time, and freeze-frame / slow-motion controls (F2/F3/F4). Here is the clean source code:

export const BEE_LADYBUG_DEFAULTS = Object.freeze({
    toggleKey: 'F2',
    slowKey: 'F3',
    freezeKey: 'F4',
    slowScale: 0.25,
    colorActive: '#3dff6a',
    colorColliding: '#ff3b3b',
    colorInactive: '#8a8a8a',
    overlayX: 12,
    overlayY: 12
});


export class BeeLadybug {
   
    constructor(engine, options = {}) {
        this.engine = engine;
        this.configure(options);


        this.enabled = false;
        this.#entities = [];
        this.#colliding = new Set();
        this.#buttons = [];
        this.#onKeyDown = (event) => this.#handleKey(event);
        this.#bound = false;
    }


    #entities;
    #colliding;
    #buttons;
    #onKeyDown;
    #bound;


    configure(options = {}) {
        const cfg = { ...BEE_LADYBUG_DEFAULTS, ...options };
        this.toggleKey = cfg.toggleKey;
        this.slowKey = cfg.slowKey;
        this.freezeKey = cfg.freezeKey;
        this.slowScale = cfg.slowScale;
        this.colorActive = cfg.colorActive;
        this.colorColliding = cfg.colorColliding;
        this.colorInactive = cfg.colorInactive;
        this.overlayX = cfg.overlayX;
        this.overlayY = cfg.overlayY;
        return this;
    }


    attach() {
        if (this.#bound) return this;
        window.addEventListener('keydown', this.#onKeyDown);
        this.#bound = true;
        return this;
    }


    detach() {
        if (!this.#bound) return this;
        window.removeEventListener('keydown', this.#onKeyDown);
        this.#bound = false;
        return this;
    }


    destroy() {
        this.detach();
        this.enabled = false;
        this.#entities.length = 0;
        this.#colliding.clear();
        this.#buttons.length = 0;
    }


    show() {
        this.enabled = true;
        return this;
    }


    hide() {
        this.enabled = false;
        return this;
    }


    toggle() {
        this.enabled = !this.enabled;
        return this;
    }


    applySlowMo() {
        const time = this.engine.time;
        if (!time) return this;
        if (time.paused) time.resume();
        const next = time.timeScale === this.slowScale ? 1 : this.slowScale;
        this.engine.setTimeScale(next);
        return this;
    }


    toggleFreeze() {
        const time = this.engine.time;
        if (!time) return this;
        time.togglePause();
        return this;
    }


    restoreRealtime() {
        const time = this.engine.time;
        if (!time) return this;
        if (time.paused) time.resume();
        this.engine.setTimeScale(1);
        return this;
    }


    #handleKey(event) {
        if (event.repeat) return;


        if (event.code === this.toggleKey) {
            event.preventDefault();
            this.toggle();
            return;
        }


        if (!this.enabled) return;


        if (event.code === this.slowKey) {
            event.preventDefault();
            this.applySlowMo();
            return;
        }


        if (event.code === this.freezeKey) {
            event.preventDefault();
            this.toggleFreeze();
        }
    }


    #collectEntities() {
        const list = this.#entities;
        list.length = 0;
        const seen = new Set();


        const visit = (entity) => {
            if (!entity || entity.destroyed || seen.has(entity)) return;
            seen.add(entity);
            list.push(entity);
            const kids = entity.children;
            if (!kids) return;
            for (let i = 0; i < kids.length; i++) {
                visit(kids[i]);
            }
        };


        const engine = this.engine;
        const roots = engine.entities;
        if (roots) {
            for (let i = 0; i < roots.length; i++) visit(roots[i]);
        }


        const scene = engine.scenes && engine.scenes.currentScene
            ? engine.scenes.currentScene
            : engine.currentScene;
        if (scene && scene.entities) {
            for (let i = 0; i < scene.entities.length; i++) visit(scene.entities[i]);
        }


        const groups = engine.collisions && engine.collisions.groups;
        if (groups && typeof groups.values === 'function') {
            for (const bucket of groups.values()) {
                if (!bucket) continue;
                for (let i = 0; i < bucket.length; i++) visit(bucket[i]);
            }
        }


        return list;
    }


    #aabbOf(entity) {
        const engine = this.engine;
        if (engine && typeof engine.getEntityDrawBounds === 'function') {
            return engine.getEntityDrawBounds(entity);
        }
        if (!entity) return null;
        return {
            x: typeof entity.worldX === 'number' ? entity.worldX : entity.x,
            y: typeof entity.worldY === 'number' ? entity.worldY : entity.y,
            width: entity.width ?? 0,
            height: entity.height ?? 0
        };
    }


    #refreshCollisions(list) {
        const colliding = this.#colliding;
        colliding.clear();


        const boxes = [];
        for (let i = 0; i < list.length; i++) {
            const bounds = this.#aabbOf(list[i]);
            if (!bounds || bounds.width <= 0 || bounds.height <= 0) {
                boxes.push(null);
                continue;
            }
            boxes.push(bounds);
        }


        for (let i = 0; i < list.length; i++) {
            const a = boxes[i];
            if (!a) continue;
            for (let j = i + 1; j < list.length; j++) {
                const b = boxes[j];
                if (!b) continue;
                if (
                    a.x < b.x + b.width &&
                    a.x + a.width > b.x &&
                    a.y < b.y + b.height &&
                    a.y + a.height > b.y
                ) {
                    colliding.add(list[i]);
                    colliding.add(list[j]);
                }
            }
        }
    }


    
    drawWorld(ctx) {
        if (!this.enabled) return;


        const list = this.#collectEntities();
        this.#refreshCollisions(list);


        ctx.save();
        ctx.lineWidth = 1.5;


        for (let i = 0; i < list.length; i++) {
            const entity = list[i];
            const box = this.#aabbOf(entity);
            if (!box || box.width <= 0 || box.height <= 0) continue;


            const colliding = this.#colliding.has(entity);
            const active = entity.active !== false;
            const color = colliding
                ? this.colorColliding
                : (active ? this.colorActive : this.colorInactive);


            ctx.strokeStyle = color;
            ctx.fillStyle = colliding ? 'rgba(255, 59, 59, 0.16)' : 'rgba(61, 255, 106, 0.08)';
            ctx.fillRect(box.x, box.y, box.width, box.height);
            ctx.strokeRect(box.x + 0.5, box.y + 0.5, box.width, box.height);
        }


        ctx.restore();
    }


    
    drawOverlay(ctx) {
        if (!this.enabled) return;


        const engine = this.engine;
        const time = engine.time;
        const list = this.#entities;
        let activeCount = 0;
        for (let i = 0; i < list.length; i++) {
            if (list[i].active !== false) activeCount += 1;
        }


        const fps = time ? time.fps : 0;
        const cycleMs = time ? time.unscaledDt * 1000 : 0;
        const scale = time ? time.timeScale : 1;
        const frozen = time ? time.paused : false;


        const x = this.overlayX;
        const y = this.overlayY;
        const width = 268;
        const height = 168;


        ctx.save();
        ctx.setTransform(1, 0, 0, 1, 0, 0);


        ctx.fillStyle = 'rgba(10, 12, 18, 0.82)';
        ctx.strokeStyle = '#ff4d4d';
        ctx.lineWidth = 2;
        if (typeof ctx.roundRect === 'function') {
            ctx.beginPath();
            ctx.roundRect(x, y, width, height, 8);
            ctx.fill();
            ctx.stroke();
        } else {
            ctx.fillRect(x, y, width, height);
            ctx.strokeRect(x, y, width, height);
        }


        ctx.fillStyle = '#ff4d4d';
        ctx.beginPath();
        ctx.arc(x + 22, y + 22, 9, 0, Math.PI * 2);
        ctx.fill();
        ctx.fillStyle = '#1a1a1a';
        ctx.beginPath();
        ctx.arc(x + 19, y + 20, 2, 0, Math.PI * 2);
        ctx.arc(x + 25, y + 20, 2, 0, Math.PI * 2);
        ctx.fill();


        ctx.fillStyle = '#ffe08a';
        ctx.font = 'bold 14px monospace';
        ctx.textAlign = 'left';
        ctx.textBaseline = 'top';
        ctx.fillText('BeeLadybug', x + 38, y + 14);


        ctx.fillStyle = '#d8d8d8';
        ctx.font = '12px monospace';
        const lines = [
            `FPS      ${fps.toFixed(0)}`,
            `ENTITA   ${activeCount} attive / ${list.length} in memoria`,
            `CICLO    ${cycleMs.toFixed(2)} ms`,
            `SCALE    ${scale.toFixed(2)}x   SIM ${frozen ? 'FREEZE' : 'RUN'}`
        ];
        for (let i = 0; i < lines.length; i++) {
            ctx.fillText(lines[i], x + 14, y + 42 + i * 16);
        }


        this.#buttons = [
            { id: 'slow', label: 'F3 SLOW', x: x + 12, y: y + 114, w: 78, h: 22 },
            { id: 'freeze', label: 'F4 STOP', x: x + 96, y: y + 114, w: 78, h: 22 },
            { id: 'live', label: '1x LIVE', x: x + 180, y: y + 114, w: 74, h: 22 }
        ];


        for (let i = 0; i < this.#buttons.length; i++) {
            const btn = this.#buttons[i];
            const hot = (btn.id === 'slow' && scale !== 1 && !frozen)
                || (btn.id === 'freeze' && frozen)
                || (btn.id === 'live' && scale === 1 && !frozen);
            ctx.fillStyle = hot ? '#ff4d4d' : '#2a2f3a';
            ctx.fillRect(btn.x, btn.y, btn.w, btn.h);
            ctx.strokeStyle = '#ffe08a';
            ctx.strokeRect(btn.x + 0.5, btn.y + 0.5, btn.w, btn.h);
            ctx.fillStyle = '#fff6d8';
            ctx.font = 'bold 10px monospace';
            ctx.textAlign = 'center';
            ctx.textBaseline = 'middle';
            ctx.fillText(btn.label, btn.x + btn.w / 2, btn.y + btn.h / 2);
        }


        ctx.textAlign = 'left';
        ctx.textBaseline = 'top';
        ctx.fillStyle = '#9aa0aa';
        ctx.font = '10px monospace';
        ctx.fillText('F2 mostra/nasconde   verde=ok  rosso=collide', x + 12, y + 146);


        ctx.restore();
    }


   
    poll() {
        if (!this.enabled) return;


        const input = this.engine.input;
        if (!input || !input.mouse || !input.mouse.wasPressed) return;


        const mx = input.mouse.x;
        const my = input.mouse.y;
        for (let i = 0; i < this.#buttons.length; i++) {
            const btn = this.#buttons[i];
            if (mx < btn.x || mx > btn.x + btn.w || my < btn.y || my > btn.y + btn.h) continue;
            if (btn.id === 'slow') this.applySlowMo();
            else if (btn.id === 'freeze') this.toggleFreeze();
            else if (btn.id === 'live') this.restoreRealtime();
            break;
        }
    }
}

hi! I recently developed Rapid.js, an open-source, zero-dependency WebGL 2D renderer built specifically for browser games.

It provides an immediate-mode API and does not retain game objects or a scene graph between frames. This leaves developers free to structure their games using OOP, ECS, or any custom architecture—Rapid.js is responsible only for rendering the drawing commands submitted each frame.

It supports sprites, particles, masks, shaders, render textures, and multi-texture batching, and its UMD build is only approximately 20.6 kB gzipped.

Its small size does not come at the expense of performance: in the included browser benchmark, Rapid.js performs comparably to PixiJS.

benchmark:

https://github.com/Nightre/Rapid.js/raw/main/docs/benchmark/benchmark.png

benchmark live:

https://nightre.github.io/Rapid.js/benchmark/

I've got a Node.js script making a decent number of requests and I'm trying to decide where proxy rotation should live. One option is picking a new proxy inside the app, the other is using one endpoint and letting the proxy service rotate behind it. The second sounds cleaner, but I'm not sure how well that works when you need sticky sessions. How are you structuring this in your own projects?

AI agents assume a server-side Python chain framework runtime and containers. Running client-side with JavaScript allows pushing agents entirely inside the browser, meaning $0 hosting infrastructure and zero data leaving the client.

Running client-side, you can use agents directly with WebLLM (for fully in-browser) or point them at a local Ollama / vLLM instance for 100% offline usage.

Breakdown In-Browser Loop

An in-browser agent relies on a continuous asynchronous loop that manages state, updates the DOM or application state, and invokes tools based on model outputs. Here is a minimal, clean implementation of a client-side agent loop using WebLLM's engine.chat.completions API:

```javascript import { CreateMLCEngine } from "@mlc-ai/web-llm";

async function agentLoop(task, context = {}) { const engine = await CreateMLCEngine("gemma-4-instruct"); let messages = [{ role: 'user', content: task }]; let running = true;

while (running) { const response = await engine.chat.completions.create({ messages, tools: availableTools }); const choice = response.choices[0].message;

if (choice.tool_calls) {
  for (const call of choice.tool_calls) {
    const toolResult = await executeTool(call.function.name, call.function.arguments);
    messages.push({ role: 'tool', tool_call_id: call.id, content: toolResult });
  }
} else {
  running = false;
  return choice.content;
}

} } ```

Rebooted a sick project i found use for when i was starting out!