Full-Stack JavaScript Developer Roadmap

What JavaScript is, where it runs (browser and Node.js), and how the language has evolved since ES2015.

The event loop, Promises, async/await, Promise.all, and common async pitfalls to avoid.

Named vs default exports, re-exporting, and code-splitting with dynamic import().

Primitives, interfaces vs type aliases, union/intersection types, arrays, tuples, and optional/readonly properties.

Creating branches, fast-forward vs merge commits, and resolving a merge conflict.

JSX syntax rules, function components, props, and composing components together.

Managing component state with useState, the rules of hooks, and useRef for DOM access.

useEffect, dependency arrays, cleanup functions, and fetching data with loading and error states.

The spacing scale, typography, color utilities, and layout utilities like flex, grid and width/height.

What Node.js is, V8 and libuv conceptually, installing Node, and your first script.

CommonJS vs ES modules, and npm basics: package.json, dependencies, and installing packages.

A complete small Express app: routes, middleware, route params, JSON bodies, and error handling.

REST principles, HTTP verbs mapped to CRUD, and a resource-oriented URL design example.

API keys, JWT bearer tokens and signature verification, and the OAuth2 authorization code flow.

How JSON Web Tokens work, how to sign and verify them, access vs refresh tokens, and the mistakes that make JWTs insecure.

The document model, when it fits better than relational, and connecting via mongosh.

Embedding vs referencing, the core MongoDB modeling decision, and schema validation rules.

What PostgreSQL is, why teams choose it over MySQL, and connecting via psql.

Implementing cache-aside with real Redis commands, plus the cache stampede problem and mitigations.

Building an API with Route Handlers, mutating data with Server Actions, and when to use each.

Full-duplex vs HTTP request/response, the upgrade handshake, and when (not) to use WebSockets.

Unit tests, mocking, and Supertest integration tests for an Express route.

What containers are, how they differ from VMs, installing Docker, and your first container.

A complete GitHub Actions workflow that checks out code, installs dependencies, and runs tests on every push and PR.

What NestJS is, why teams choose it over plain Express, installing the CLI, and the generated project structure.

Commonly asked Node.js interview questions with clear, practical answers.