JavaScript Mastery: Closures, Event Loop, Prototypes & Performance
Trace closures, this, prototype chains, the event loop, generators and memoization the way the engine does, and measure what your code costs, with every answer checked as you go.
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About this course
This advanced course shows you how the JavaScript engine really runs your code. In 20 hands-on labs you trace closures and private state, resolve this through call, apply, bind and arrow functions, follow prototype chains and class hierarchies, and predict the exact log order of timers, promise chains and async/await. You time sequential, parallel and pooled requests, step through generators and lazy pipelines, count the calls a memoization cache saves, and turn loops into Big-O figures. Debounce, throttle, boundary tests and an event batcher capstone connect it all. Each answer is checked instantly, the first lesson is free, and you finish with a certificate exam.
Lessons
- Lexical Scope & Closures: The Counter FactoryFree
- The Loop Closure Trap: var, let and Per-Iteration Bindings Locked
- Private State in Closures: A Fixed-Window Rate Limiter Locked
- this Without Guesswork: The Four Binding Rules and Arrows Locked
- call, apply and bind: Explicit this and Partial Application Locked
- The Prototype Chain: Lookup, Shadowing and Writes Locked
- class, extends and super: Dynamic Dispatch in Practice Locked
- Own vs Inherited Keys: for…in, Object.keys and Enumerability Locked
- Timers and the Macrotask Queue: When Does a Callback Really Run? Locked
- Microtasks vs Macrotasks: Promise Chains Interleave Locked
- async/await Under the Hood: Counting Microtask Ticks Locked
- Sequential, Promise.all or a Pool: Timing Concurrent Work Locked
- Generators: Pausing Functions, next(value) and Spread Locked
- Lazy Pipelines: Doing Less Work with Generators Locked
- Memoization: From Exponential to Linear Calls Locked
- Debounce and Throttle: Timers Inside Closures Locked
- Complexity by Counting: Loops, Doubling and Growth Factors Locked
- Array vs Set: The Hidden Quadratic in filter + indexOf Locked
- Testing Mindset: Boundary Values Catch Off-by-One Bugs Locked
- Capstone: An Event Batcher with Closures, Timers and Limits Locked