JavaScript

Understand how JavaScript stores values using let, const, and var, and learn the seven primitive types plus objects. You will know when to use each declaration keyword and how type coercion works under the hood.

Learn arithmetic, comparison, logical, and assignment operators and how JavaScript evaluates expressions. You will understand truthy/falsy values and short-circuit evaluation.

Master if/else, switch, for, while, and for...of loops to direct program execution. You will be able to choose the right control structure for any situation.

Define functions using declarations, expressions, and arrow syntax, and understand how scope determines variable visibility. You will grasp hoisting, block scope, and the call stack.

Create and manipulate objects using literal syntax, dot and bracket notation, and computed properties. You will understand reference semantics and shallow vs deep copying.

Work with arrays using map, filter, reduce, find, and other higher-order methods. You will know when to use each method and how they compose for data transformation pipelines.

Extract values from objects and arrays with destructuring syntax, and combine or clone data with spread and rest operators. You will write cleaner, more concise code for common data manipulation patterns.

Use Map, Set, WeakMap, and WeakSet for specialized collection needs beyond plain objects and arrays. You will understand when these structures outperform their plain counterparts.

Understand how inner functions capture variables from their enclosing scope, creating closures. You will use closures for data privacy, factory functions, and event handlers.

Learn how the value of 'this' is determined by call site, and control it with bind, call, and apply. You will debug common 'this' pitfalls in callbacks and methods.

Write functions that accept or return other functions, enabling powerful abstraction patterns. You will understand the callback pattern that underpins event handling, array methods, and async code.

Understand JavaScript's prototype chain and how objects delegate property lookups to their prototypes. You will see how this differs from classical inheritance and why it matters.

Use ES6 class syntax for constructors, methods, getters/setters, static members, and inheritance with extends. You will understand that classes are syntactic sugar over prototypes.

Apply object composition and mixin patterns as alternatives to deep inheritance hierarchies. You will learn when composition leads to more flexible and maintainable designs.

Understand JavaScript's single-threaded event loop, the call stack, callback queue, and microtask queue. You will be able to predict the execution order of synchronous and asynchronous code.

Create and chain promises to handle asynchronous operations with .then(), .catch(), and .finally(). You will understand promise states, error propagation, and Promise.all/race/allSettled.

Write asynchronous code that reads like synchronous code using async functions and the await keyword. You will handle errors with try/catch and understand how async/await desugars to promises.

Create custom iterable objects with Symbol.iterator and use generator functions with yield for lazy evaluation. You will understand how for...of works under the hood.

Handle runtime errors gracefully using try/catch/finally, create custom error classes, and understand the built-in error hierarchy. You will write resilient code that fails predictably.

Use browser DevTools and console methods effectively — breakpoints, watch expressions, the network tab, and stack traces. You will systematically diagnose and fix bugs instead of guessing.

Organize code into reusable modules using import and export syntax, understanding named vs default exports, re-exports, and static analysis benefits. You will structure projects for maintainability.

Understand Node.js require/module.exports, how it differs from ES modules, and the historical evolution of JavaScript module systems including AMD and UMD.

Use template literals for string interpolation and multiline strings, and write tagged template functions for DSLs and sanitization. You will move beyond string concatenation to expressive string handling.

Use Symbol to create unique property keys and leverage well-known symbols like Symbol.iterator and Symbol.toPrimitive to customize object behavior. You will understand metaprogramming basics.

Intercept and customize fundamental object operations using Proxy traps and the Reflect API. You will understand how frameworks use proxies for reactivity, validation, and access control.

Safely access nested properties and provide defaults using ?. and ?? operators. You will write more defensive code without verbose null-checking boilerplate.

Select, create, modify, and remove HTML elements using querySelector, createElement, and the DOM API. You will understand the document tree and how JavaScript interacts with the rendered page.

Attach event listeners, understand the capture/bubble phases, and use event delegation for efficient handling of dynamic content. You will build interactive UIs that respond to user actions.

Make network requests with the Fetch API, handle JSON responses, manage headers and CORS, and process errors. You will connect front-end applications to back-end services.

Persist data in the browser using localStorage, sessionStorage, IndexedDB, and cookies. You will choose the right storage mechanism based on capacity, lifetime, and security needs.

Understand how JavaScript's garbage collector reclaims memory, identify common memory leak patterns, and use DevTools to profile heap usage. You will write applications that perform well over time.

Apply patterns like module, observer, factory, singleton, and strategy in JavaScript. You will recognize when a pattern simplifies your architecture and when it adds unnecessary complexity.

Use pure functions, immutability, currying, partial application, and function composition to write predictable, testable code. You will blend functional and object-oriented styles effectively.

Write unit tests with frameworks like Jest or Vitest, understand assertions, mocking, and test-driven development. You will gain confidence that your code works correctly through automated testing.