Error Handling in Node.js: The Missing Guide

Most Node.js tutorials skip error handling. Here's what they don't tell you.

The Three Types of Errors

// 1. Operational Errors (expected, handle them) // - File not found, network timeout, invalid input // - These ARE going to happen. Plan for them.

// 2. Programmer Errors (bugs, fix them) // - TypeError, ReferenceError, logic errors // - These should NOT happen. Fix the code.

// 3. System Errors (infrastructure, retry them) // - Out of memory, connection refused, DNS failure // - Often transient. Retry with backoff.

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Synchronous Error Handling

// Use try/catch for synchronous code function parseConfig ( filePath ) { try { const raw = fs . readFileSync ( filePath , ' utf8 ' ); return JSON . parse ( raw ); } catch ( err ) { if ( err . code === ' ENOENT ' ) { console . error ( `Config file not found: ${ filePath } ` ); return getDefaultConfig (); } if ( err instanceof SyntaxError ) { console .…