javascript-fundamentals

Closures allow functions to access variables from their outer scope, enabling data encapsulation and callbacks. Async/await is modern syntax for handling asynchronous operations like API calls, built on Promises, making code more readable than nested callbacks or .then() chains.

ES6+ refers to modern JavaScript standards introducing arrow functions, destructuring, template literals, classes, and modules. These features improve code clarity, reduce boilerplate, and are standard across frontend frameworks and Node.js backends.

Memory leaks occur when objects remain in memory unnecessarily, often through closures holding references or event listeners not being removed. Optimization involves understanding scope, managing closures carefully, and profiling with browser or Node.js tools to identify bottlenecks.

Promises represent eventual asynchronous results and use .then() chaining. Async/await provides syntactic sugar over Promises, allowing code to read synchronously while remaining non-blocking, reducing callback nesting and improving readability.

Module patterns encapsulate code by using closures to create private variables and public interfaces, preventing namespace pollution. Modern ES6 modules with import/export statements standardize this practice for maintainable, reusable code in both browsers and Node.js.

Yes, core JavaScript concepts like closures, async/await, Promises, and module patterns are fundamental to Node.js development and apply directly to server-side code, APIs, and service architecture.