Inside JavaScript Memory: Visualizing Allocation, GC, and Leak Detection
See the Invisible
Interactive simulators visualize what's hidden from view.
Hands-On Labs
Step through executions tick by tick. Manipulate state.
Why, Not Just What
Deep architectural understanding for mid-senior developers.
AI Sandbox Lab
Real-world scenarios. Find the flaws AI misses.
Become the Engineer Who Supervises AI
As AI generates more code, understanding what that code does becomes more valuable, not less. Someone must verify AI output, debug failures, and make architectural decisions.
Build Your Architectural EdgeMemory Is Invisible. Your Bugs Aren't.
Every JavaScript developer has spent hours hunting a memory leak with nothing but console.log and trial and error. This course makes the invisible visible.
The Problem
- You know objects behave differently from primitives, but you can't explain why mutations propagate through your code
- Heap snapshots look like spreadsheets of gibberish. Retained size, retainer chains, shallow size: meaningless numbers
- Production memory keeps growing. You removed the DOM node. You set the variable to null. The leak persists.
After This Course
- You see memory as two distinct regions: stack for primitives and call frames, heap for objects and their reference graphs
- You read heap snapshots fluently, tracing retainer chains from leaked objects back to GC roots
- You identify the hidden reference path keeping leaked memory alive and fix it systematically
Interactive Simulators: Watch Memory Behave
Reading about garbage collection is one thing. Watching the mark phase traverse your object graph and the sweep phase reclaim unreachable nodes is another. Each simulator in this course visualizes a specific memory behavior: primitive vs object assignment, reference graph formation, reachability tracing from GC roots, closure scope retention, and event listener accumulation. You build accurate mental models by observing the system in motion.
What You'll Master
Stack vs Heap Architecture
Where primitives and objects actually live. Why the stack auto-cleans while the heap requires garbage collection.
Object Graphs & References
How objects reference other objects, creating directed graphs. Nested objects, circular references, and shared reference targets.
Reachability & Mark-and-Sweep
The algorithm that decides what survives. GC roots, reachability paths, the mark phase, and the sweep phase animated step by step.
Memory Leak Mechanics
A leak is not forgotten memory. It is unintentionally reachable memory. The three conditions that create a leak and why GC cannot help.
Three Leak Patterns
Closure retention, event listener accumulation, and detached DOM nodes. Each pattern visualized with its hidden reference path exposed.
Heap Snapshot Analysis
Read heap snapshots with confidence. Understand shallow vs retained size. Trace retainer chains back to GC roots to find leak sources.
Course Curriculum
11 lessons. 3 architecture deep-dives. 8 interactive simulators.
Visual cheatsheet
Practice verifying AI-generated code
Built for engineers who debug production memory issues, optimize application performance, and need to understand what the garbage collector actually sees.
Stop guessing why memory grows. Start seeing the reference paths that keep it alive.
Ready to see what's really happening?
All deep dives included with your subscription. Cancel anytime.