Master complex concepts and patterns
0%
Completed
Understanding closures and lexical scope
More closure exercises
Understanding JavaScript's prototype chain
How JavaScript handles async code
Creating custom iteration with generators
Intercept and customize object operations
Memory-efficient collections for objects
Transform functions for flexibility
8 premium lessons are waiting for you
The interactive JavaScript sandbox is available only for premium members. You can still learn from the free lessons and practice challenges, and upgrade anytime to unlock the full sandbox experience.