## 1. **Core JavaScript (ES6 and beyond)*

• Variables & Scope: var, let, const, block scope vs. function scope.
• Data Types: Primitive vs. reference types, type coercion, typeof, NaN, null vs. undefined.
• Operators: Arithmetic, comparison, logical, ternary, spread/rest, optional chaining (?.).
• Control Flow: if-else, switch, for, while, do-while, for...in, for...of.
• Functions: Declarations, expressions, arrow functions, default/rest parameters, IIFE.
• Hoisting and Temporal Dead Zone.
• Closures and Lexical Scope.
• this keyword & binding (call, apply, bind).
• Prototypes & Prototype Chain.
• Objects & Arrays: Creation, destructuring, methods (Object.keys, Object.assign, spread, rest).
• DOM Manipulation: querySelector, events, event delegation.
• ES6+ Features: Template literals, modules (import/export), classes, async/await, Promise.allSettled, optional chaining, nullish coalescing.

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2. Advanced JavaScript Concepts

• Event Loop & Concurrency: Call stack, web APIs, microtasks vs. macrotasks.
• Promises & Async/Await: Error handling with try...catch.
• Error Handling: throw, try...catch, custom errors.
• Memory Management: Garbage collection basics.
• Higher-Order Functions: map, filter, reduce, forEach.
• Generators & Iterators.
• Modules & Bundling: ES Modules, CommonJS, tree-shaking basics.
• Fetch API & AJAX: JSON parsing, handling HTTP errors.

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3. Browser APIs and DOM

• DOM Tree Structure and traversal.
• Events: Bubbling, capturing, delegation.
• LocalStorage, SessionStorage, Cookies.
• Timers: setTimeout, setInterval, requestAnimationFrame.
• Form Handling & Validation.
• Geolocation, Fetch, and other modern APIs.

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4. Object-Oriented Programming in JS

• Classes & Constructors.
• Inheritance: extends, super.
• Encapsulation: Private fields, getters, setters.
• Polymorphism and method overriding.

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5. Functional Programming Basics

• Immutability.
• Pure Functions.
• Currying & Partial Application.
• Composition.

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6. Data Structures & Algorithms in JS

• Arrays: Sorting, searching, two-pointer problems.
• Strings: Reversal, palindrome checks.
• Objects & Maps/Sets: Usage and performance differences.
• Recursion: Factorials, Fibonacci.
• Common Patterns: Sliding window, hashing, stack/queue usage.

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7. Testing and Best Practices

• Debugging Tools: console, breakpoints in DevTools.
• Code Quality: Linting (ESLint), formatting (Prettier).
• Unit Testing Basics: Jest or Mocha (optional for interviews).
• Performance Optimization: Debouncing, throttling.

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8. Bonus Topics (for Full-Stack or Senior Roles)

• TypeScript basics (type annotations, interfaces).
• Build Tools: Webpack, Vite basics.
• React Basics: JSX, components, props, state.
• Security: XSS, CSRF, CORS basics.

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