Lesson overview · Free interview practice

Memory Leaks

Learn to identify and prevent memory leaks.

Topics in the full lesson
  • Understanding Memory Management in JavaScript
  • Common Causes of Memory Leaks
  • Identifying Memory Leaks
  • Tools for Detecting Memory Leaks
  • Best Practices for Preventing Memory Leaks
  • Advanced Techniques
  • Exercises

Practice Problems

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TheoryEasy

Common Memory Leak Patterns in JavaScript

Question

What are the most common memory leak patterns in JavaScript applications?

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Explain your reasoning or try an implementation before comparing answers.

TheoryEasy

Modern Cleanup Patterns: `AbortController` + Framework Cleanup

Question

What does modern, leak-free cleanup look like in browser apps? Show the canonical patterns for listeners, observers, and framework integration.

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TheoryMedium

Detached DOM Trees

Question

What is a detached DOM tree, and why does a single reference to a removed element retain the whole subtree? Show how WeakMap-as-cache prevents this.

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TheoryMedium

Closures and the Captured-Too-Much Pattern

Question

How can closures cause memory leaks, and how do you spot and fix the "captured too much" pattern?

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TheoryMedium

Identifying Memory Leaks with Chrome DevTools

Question

How do you use Chrome DevTools to identify a memory leak in a web app? Walk through the heap-snapshot workflow.

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