{"id":51851578,"url":"https://github.com/shahjabir/js-runtime-lab","last_synced_at":"2026-07-23T20:00:54.224Z","repository":{"id":336306604,"uuid":"1146727306","full_name":"ShahJabir/js-runtime-lab","owner":"ShahJabir","description":"Learn Node.js beyond frameworks. 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Not a framework crash course.**\n\u003e This repository is a **deep, internals-first journey into JavaScript/TypeScript runtimes** — from the engine and event loop up through Node.js, Deno, Bun, and Cloudflare Workers.\n\nIf you are here to _\"learn Express\"_ or _\"learn a framework\"_, this repo is **not for you**.\nIf you want to **understand what a JS runtime really is and how it works under the hood — in all its current forms**, welcome.\n\n![Alt](https://repobeats.axiom.co/api/embed/abce5e301e4393e503fdfb70248e5d576ec8da16.svg \"Repobeats analytics image\")\n\n---\n\n## 🎯 Purpose of This Repository\n\nThis repository exists to:\n\n- Understand **runtimes as systems**, not just \"places JS runs\"\n- Learn **core/native APIs** in every runtime before reaching for a framework\n- Build **deep intuition** for the event loop, I/O, and concurrency models each runtime uses\n- Understand the **engines** underneath (V8, JavaScriptCore) and how each runtime embeds them\n- Compare runtimes **against each other**, not just learn them in isolation\n- Learn how each runtime achieves **async I/O, isolation, and performance**\n- Read and understand **runtime source code and specs** confidently\n- Explore **edge computing architecture** through Cloudflare Workers\n\nThis is a **learning log + reference + code lab**.\n\n---\n\n## 🧠 Philosophy\n\n```text\nFrameworks come and go.\nRuntimes and their internals stay forever.\n```\n\nPrinciples followed in this repo:\n\n- ❌ No Express / Nest / Fresh / Hono without understanding what's underneath\n- ❌ No unnecessary npm packages when a native/core API does the job\n- ✅ Core/native APIs first, in every runtime\n- ✅ Source-code and spec curiosity over blog-post trust\n- ✅ Performance and correctness over convenience\n- ✅ Understanding \"why\", not just \"how\"\n\nWhenever possible, things are built **from scratch using each runtime's native APIs**.\n\n---\n\n## 🗺️ Learning Scope\n\nThis repository covers **far more than just Node.js**:\n\n- JavaScript engine internals (V8, JavaScriptCore) — event loop, memory, JIT basics\n- TypeScript — type system internals, not just syntax\n- Node.js architecture — libuv, async I/O, streams, native addons\n- Deno — permission model, Web-standard APIs, secure-by-default design\n- Bun — Zig-based runtime, native bundler/test runner, JavaScriptCore integration\n- Cloudflare Workers — V8 isolates, `workerd`, Durable Objects, edge-native storage (D1/KV/R2)\n- Cross-runtime comparisons — where these runtimes agree, diverge, and why\n\nThink of this as:\n\n\u003e **Systems Engineering through the lens of JavaScript Runtimes**\n\n---\n\n## 📍 Current Focus\n\n```text\nPhase 1 → JavaScript \u0026 TypeScript Core (engine-level)\nPhase 2 → Node.js Internals\nPhase 3 → Deno\nPhase 4 → Bun\nPhase 5 → Cloudflare Workers\nPhase 6 → Cross-Runtime Systems \u0026 Architecture\n```\n\nSee [`LEARNING_LOG.md`](./LEARNING_LOG.md) for the running journal and [`RESOURCES.md`](./RESOURCES.md) for the curated reading list per phase.\n\n---\n\n## 📦 Core Rule: Depth Before Breadth\n\nEvery topic explored here follows the same progression:\n\n1. **What is it?** — Conceptual foundation\n2. **How does it work?** — Internal mechanics\n3. **Why is it designed this way?** — Trade-offs and history\n4. **Where does it break?** — Failure modes and edge cases\n5. **How do I use it well?** — Practical, performance-aware application\n\nExternal frameworks and GUIs are only discussed **conceptually** or for comparison — native APIs, CLIs, and official docs are the primary interface.\n\n---\n\n## 🧪 How to Use This Repository\n\n### 1️⃣ Read\n\nEach directory contains **Markdown notes** explaining concepts, internals, and trade-offs — not just \"how to.\"\n\n### 2️⃣ Code\n\nEvery concept is backed by small, runnable experiments — minimal examples, no boilerplate.\n\n### 3️⃣ Break Things Intentionally\n\n- Block the event loop\n- Exhaust memory\n- Flood sockets\n- Force a Worker isolate to cold-start under load\n- Compare the same program's behavior across Node, Deno, and Bun\n\nThen understand **why it broke** and what the runtime was doing.\n\n---\n\n## 🚀 Who This Repo Is For\n\nThis repository is ideal for:\n\n- Backend engineers who want **real depth**, not framework fluency\n- Security engineers who need to understand runtime attack surfaces\n- Systems programmers curious about how JS runtimes are actually built\n- Developers moving beyond frameworks\n- Anyone who wants to read Node/Deno/Bun/`workerd` source code and follow it\n\nThis repo is **not beginner-friendly** — and that is intentional.\n\n---\n\n## 📌 Expected Outcome\n\nAfter completing this repository, you should be able to:\n\n- Explain the event loop and I/O model of Node, Deno, and Bun — and where they differ\n- Build servers without frameworks, on any of the four runtimes\n- Write memory-efficient streaming systems\n- Debug event-loop blocking and isolate cold-start issues\n- Reason about V8 isolates vs OS processes vs containers\n- Design an edge-native architecture on Cloudflare Workers (Durable Objects, D1, KV, R2, Queues)\n- Learn any new JS-runtime-adjacent tool effortlessly, because the fundamentals are solid\n\n---\n\n## ⚠️ Disclaimer\n\nThis repository is:\n\n- Opinionated\n- Internals-focused\n- Performance-oriented\n\nIt prioritizes **understanding over speed** and **depth over comfort**.\n\nNotes here may contradict conventional wisdom — when they do, there will always be a reason.\n\n---\n\n## 👤 Author\n\n\u003cp align=\"center\"\u003e\n\u003ca href=\"https://shahjabir.com.bd\"\u003e\n\u003cimg src=\"https://img.shields.io/badge/Website-ShahJabir-black\" alt=\"Website\" /\u003e\u003c/a\u003e\n\u003ca href=\"https://github.com/ShahJabir\"\u003e\n\u003cimg src=\"https://img.shields.io/badge/Github-ShahJabir-white\" alt=\"Github\" /\u003e\u003c/a\u003e\n\u003ca href=\"https://www.facebook.com/sjtaqi\"\u003e\n\u003cimg src=\"https://img.shields.io/badge/Facebook-ShahJabir-blue\" alt=\"Facebook\" /\u003e\u003c/a\u003e\n\u003ca href=\"https://x.com/TaqiJabir\"\u003e\n\u003cimg src=\"https://img.shields.io/badge/X-TaqiJabir-black\" alt=\"Twitter\" /\u003e\n\u003c/a\u003e\n\u003ca href=\"https://www.linkedin.com/in/shahjabir/\"\u003e\n\u003cimg src=\"https://img.shields.io/badge/Linkedin-shahjabirtaqi-blue\" alt=\"Linkedin\" /\u003e\u003c/a\u003e\n\u003c/p\u003e\n\n---\n\n## 📄 License\n\nThis repository is licensed under the [MIT License](./LICENSE).\nAll notes, diagrams, and code are original work unless explicitly cited.\n\n---\n\n## 🏁 Final Words\n\n```text\nMost people use a JS runtime.\nVery few understand more than one.\nThis repo is for the second group.\n```\n\nHappy Noding, Denoing, Bunning, and Working 🚀\n","project_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fshahjabir%2Fjs-runtime-lab","html_url":"https://awesome.ecosyste.ms/projects/github.com%2Fshahjabir%2Fjs-runtime-lab","lists_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fshahjabir%2Fjs-runtime-lab/lists"}