Node.js leaks overview

Node processes often run days or weeks. A few KB leaked per request × millions of requests = outage.

Server leak patterns in this course

Pattern	Runnable example
Global growing array	`examples/node/01-global-array-leak.js`
EventEmitter listeners	`examples/node/02-event-emitter-leak.js`
Closure cache	`examples/node/03-closure-cache-leak.js`
Timers keeping loop alive	`examples/node/04-timer-handle-leak.js`
Unclosed streams	`examples/node/05-stream-leak.js`

Each has a paired *-fixed.js version.

How to run examples

From the project root:

node --expose-gc --inspect examples/node/01-global-array-leak.js

Then open chrome://inspect → inspect your Node target → Memory tab.

See examples/node/README.md in the repo for full instructions.

# Watch memory in terminal
node examples/node/01-global-array-leak.js

# With manual GC (compare leak vs fix)
node --expose-gc examples/node/01-global-array-fixed.js