Mastering JavaScript: 10 Concepts Every Developer Should Know

JavaScript is one of the most powerful and widely used programming languages. Whether you're a beginner or an experienced developer, mastering these core concepts will help you write cleaner, more efficient, and scalable code.

1. Closures Closures allow functions to "remember" the scope in which they were created. They are useful for data privacy and function factories. Example: function outerFunction(outerVariable) { return function innerFunction(innerVariable) { console.log(Outer: ${outerVariable}, Inner: ${innerVariable}); }; }

const closureExample = outerFunction("Hello");
closureExample("World"); // Output: Outer: Hello, Inner: World

1. Hoisting Hoisting is JavaScript's default behavior of moving variable and function declarations to the top of their scope before execution.

Example:
console.log(hoistedVar); // Undefined (not an error)
var hoistedVar = "I am hoisted";

hoistedFunction(); // Works because function declarations are hoisted
function hoistedFunction() {
console.log("I am hoisted too!");
}

1. The Event Loop The event loop enables JavaScript’s asynchronous behavior, allowing non-blocking operations using callbacks, promises, and async/await.

Example:
console.log("Start");

setTimeout(() => {
console.log("Inside setTimeout");
}, 0);

console.log("End");