A practical, open-source TypeScript curriculum for learning from first principles to production-ready patterns.
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Note
This course is actively being completed. Foundations is available now, Phase 2 is underway, and the full 33-lesson curriculum is being released in public. Published lessons are ready to study; upcoming material is clearly marked below. See START-HERE.md for guidance, ROADMAP.md for the full plan, and PROGRESS.md for live status.
Most TypeScript resources either stop at syntax or jump to advanced types without enough practice. TypeScript Mastery is designed as a connected learning path: understand the idea, apply it in code, check your work, and use it in realistic projects.
It is built for:
- Beginners learning TypeScript for the first time
- JavaScript developers moving to type-safe code
- React and frontend developers
- Node.js and full-stack developers
- Developers preparing for TypeScript interviews
| Your goal | Recommended route | First step |
|---|---|---|
| Learn TypeScript from zero | Complete Foundations in order, then move phase by phase | Begin with Lesson 1 — What is TypeScript? |
| Move from JavaScript to TypeScript | Learn the compiler, primitives, objects, functions, and interfaces before tackling generics | Set up TypeScript and tsconfig |
| Prepare for practical work | Finish Foundations, then focus on types, narrowing, generics, APIs, and the milestone projects | Start with Foundations |
| Prepare for interviews | Follow the full path, complete each assessment, and revisit the Q&A references | Start with Lesson 1 |
Each lesson is being shaped around one repeatable loop:
Learn the concept → Study a realistic example → Solve exercises
→ Review a worked solution → Explain the idea in your own words
As the course is completed, every lesson will include concise notes, practical exercises, worked solutions, and an interview-oriented reference. Solutions are kept compilable so the repository remains useful as a code-learning resource—not only as reading material.
Open the roadmap image for the full curriculum view.
| Phase | Focus | Lessons | Availability |
|---|---|---|---|
| 1. Foundations | Types, arrays, objects, functions, interfaces | 7 | Available now |
| 2. Intermediate | Unions, generics, utility types, narrowing, modules | 7 | In progress — first lessons live |
| 3. Advanced | Advanced generics, conditional and mapped types, declaration files | 6 | Planned |
| 4. Production TypeScript | React, Next.js, Node.js, Express, API and database typing | 8 | Planned |
| 5. Enterprise TypeScript | Type architecture, reusable systems, scalable patterns | 5 | Planned |
Phase 1 — Foundations · 7 lessons · available now
Build a solid base in TypeScript's core concepts:
- What is TypeScript?
- Installation, compilation, and
tsconfig - Primitive types and arrays
- Objects and type aliases
- Functions and interfaces
Phase 2 — Intermediate · 7 lessons · in progress
Learn to model real data and write reusable types with unions, intersections, generics, enums, tuples, utility types, narrowing, and modules.
Phase 3 — Advanced · 6 lessons · planned
Master the type system through advanced generics, conditional types, mapped types, indexed access types, template literal types, and declaration files.
Phase 4 — Production TypeScript · 8 lessons · planned
Apply TypeScript to React, Next.js, Node.js, Express, API contracts, forms, authentication, and databases.
Phase 5 — Enterprise TypeScript · 5 lessons · planned
Design maintainable type architecture, reusable type systems, type-safe APIs, and scalable project structures.
As the remaining phases are published, the complete curriculum will include:
- 100+ exercises spanning fundamentals through advanced type-system patterns
- Worked solutions that explain the reasoning, not only the answer
- Phase assessments to check understanding before moving forward
- Cumulative assessments that connect earlier concepts to new ones
- Three milestone projects built around real application concerns
- Interview preparation covering questions, pitfalls, and patterns worth explaining clearly
These projects turn the curriculum into portfolio-ready practice. They will be released alongside the production-focused phases.
| Project | What you will practice |
|---|---|
| Typed Todo API | Request and response contracts, CRUD operations, Express, and TypeScript |
| Typed Express Application | Middleware, validation, authentication, error handling, and maintainable backend boundaries |
| Full-Stack Typed Application | React, Next.js, Node.js, shared types, and production-style architecture |
This repository is intentionally being built in public. You can follow the course as it grows, suggest clearer explanations, report issues, and help make the material more useful for the next learner. Read the contribution guide before opening an issue or pull request.
If you want to use this as your study space, fork it and keep a personal learning journal alongside your exercise attempts. Please use the material to learn and build—not to republish completed solutions as your own work.
TypeScript Mastery is guided by a few non-negotiable principles:
- Practical over theoretical — concepts should connect to code you would write at work.
- Clarity over cleverness — explanations should be easy to revisit months later.
- Depth without overload — one focused idea at a time, with the context to understand why it matters.
- Verified examples — solutions should compile and stay maintainable.
- Honest progress — published content, in-progress work, and future plans are clearly distinguished.
Built by Neeraj Kumar, a full-stack developer focused on creating useful software and clear educational resources.
Build deeply. Teach clearly. Improve consistently.
If TypeScript Mastery helps you learn, a star or a thoughtful issue helps more developers discover and improve it.