11 JavaScript Features Critical to Understand

Explore how scope governs variable access in JavaScript, focusing on var, function scope, and the scope chain through practical examples and nested functions.

Compare var and let to understand their scope differences across functions and blocks. Explore how hoisting affects variables and see examples of for loops showing var vs let behavior.

Understand how hoisting lifts function declarations and variables in JavaScript, compare declarations with expressions, and learn practices to avoid hoisting bugs by proper declaration and initialization.

Explore how JavaScript uses objects pervasively, with primitives promoted to object wrappers and common types like functions, arrays, date, set, and map.

Explore how prototype inheritance links objects to their prototypes, where the prototype is automatically assigned and the chain enables access to inherited properties and methods.

Learn how to set the prototype of an object using constructor functions, Object.create, and Object.setPrototypeOf, enabling prototype inheritance of methods and properties.

Discover how JavaScript treats functions as first-class values and how higher-order functions operate on other functions, especially through callbacks used in array methods like sort.

Explore the callback pattern in JavaScript, showing how to pass functions to other functions, process data, and use higher-order callbacks to make code more versatile and maintainable.

Learn how immediately invoked function expressions (IIFEs) create a local scope, avoid global variables, and run setup tasks on page load by invoking the function immediately.

Demystify closure in JavaScript by showing how inner functions retain access to scope via callbacks and set time out, and how immediately invoked function expressions and module pattern illustrate persistence.

Explore the traditional module pattern in JavaScript: a self-contained function using closure and an immediately invoked function expression to expose a public API while avoiding global name collisions.

Explore how this binding is determined at runtime by how a function is invoked, and how it relates to objects, strict mode, and explicit binding with call, apply, and bind.

Learn how promises model asynchronous operations in JavaScript, using then and catch to handle resolution or errors. Chain promises for cleaner code, and use fetch with response.json to process data.

Explore eleven crucial JavaScript concepts, from scope and hoisting to closures and promises, and learn to apply higher order functions, callbacks, immediately invoked function expressions, module pattern, and async patterns.