Mastering Modern JavaScript: A Comprehensive Guide to ES6+ Features

JavaScript has evolved dramatically since ECMAScript 6 (ES6) and subsequent releases, introducing features that enhance code readability, maintainability, and performance. Whether you're a novice aiming to write cleaner code or an experienced developer seeking efficiency, mastering ES6+ is crucial in modern web development. This guide explores key ES6+ features with practical examples, tips for real-world applications, and best practices to elevate your JavaScript skills.

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1. Block-Scoped Variables with 'let' and 'const'

let count = 1;       // Block-scoped, reassignable
const PI = 3.14159;  // Block-scoped, constant
if (true) {
  let count = 2;     // Separate scope, no conflict
  console.log(count); // 2
}
console.log(count);   // 1

Why it matters: Unlike var, let and const are block-scoped, preventing accidental variable leaks and improving code predictability. Use const for values that won’t change and let for those that might.

Pro tip: Prefer const by default to enforce immutability and reduce bugs from unintended reassignments.

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