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  • 🍔🧠 How Node.js Works Behind the Scenes (Deep Dive)

🍔🧠 How Node.js Works Behind the Scenes (Deep Dive)

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📚 Software Engineering Articles

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👨🏻‍💻 Coding Tip

  • Use Go's select with a timer for graceful timeouts in concurrent operations

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Node.js powers millions of backend applications by executing JavaScript code through an event loop with multiple specialized phases. Understanding how it works internally is crucial for writing performant server-side applications that handle concurrent operations efficiently.

The challenge: 
A runtime that can process async operations like file I/O and network requests without blocking while maintaining predictable execution order across different types of operations.

Implementation highlights:

  • Event loop phases: Multiple specialized phases (timers, poll, check etc.) to handle different types of operations efficiently

  • libuv integration: C library that provides cross-platform async I/O operations and event loop implementation

  • Poll phase optimization: Blocks efficiently waiting for I/O events rather than spinning the loop

  • process.nextTick: Special queue that runs after each phase for fine-grained control

  • Promise microtasks: Lower priority than nextTick but higher than macrotasks for predictable async execution

Results and learnings:

  • Efficient I/O: Non-blocking handling of file and network operations

  • Predictable order: Well-defined phase sequence ensures consistent execution patterns

  • Developer-friendly: Familiar JavaScript APIs while handling complex async operations under the hood

Node.js shows that with careful system design, we can build powerful server-side applications using JavaScript. Understanding the event loop phases helps write better code by working with the runtime rather than against it.

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Brief: Apple partners with Anthropic to develop an AI coding tool using Claude Sonnet for writing, editing, and testing code, potentially integrating it into Xcode for internal use first.

Brief: Uber doubles down on autonomous vehicles with a $100M investment in WeRide to expand their robotaxi partnership to 15 more cities, focusing on Europe and beyond.

Brief: Google's latest Gemini 2.5 Pro update significantly improves the AI model's coding performance, making it more efficient and accurate for developers.

Brief: Stripe now enables merchants in 100+ countries to hold and transfer funds via stablecoins (USDC and USDB), accelerating cross-border payments and deepening its fintech ecosystem.

Brief: Amazon unveils Vulcan, a touch-sensitive warehouse robot that handles 75% of inventory items, operates 20 hours/day, and aims to reduce worker injuries—but insists it’s not replacing humans.

Brief: Figma introduces AI-driven "vibe-coding", allowing users to generate functional app and website code from text prompts or existing designs, with premium access starting at $16/month and integration of Anthropic’s Claude AI model.

This week’s coding challenge:

This week’s tip:

In Go, use select with a default case and a timer to implement graceful timeouts for concurrent operations while still processing results that arrive within the time window. This pattern provides more control than context-based timeouts and allows partial results to be handled.

Wen?

  • Distributed systems: Collecting partial results from multiple services when complete responses aren't critical.

  • Resource cleanup: Gracefully shutting down goroutines while still processing in-flight requests.

  • Batch processing: Implementing "process as much as possible within time window" scenarios.

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