Category: JavaScript

Understand where variables are visible: global, function, and block.

Compare the three common scope levels with examples.

Learn how declarations are hoisted and temporal dead zones work.

Use closures to keep private state via captured variables.

Understand creation/execution of contexts and the call stack.

Write concise functions with => and lexical this.

Pass functions to be called later (events, timers, array methods).

Write functions that take/return other functions.

Expand iterables/objects with … for copies and merges.

Collect remaining values with rest syntax in bindings and parameters.