The TypeScript Roadmap

What TypeScript is, the bugs it catches before your code runs, how the compiler checks and then erases types, TypeScript 7, and your first project.

Write types on variables, parameters and return values; learn the primitive types, inference, arrays, object shapes, any, unknown, null and undefined.

Type parameters and return values, optional, default and rest parameters, void and never, callbacks, overloads, this, and functions that carry properties.

Name your own types with type and interface, extend and combine shapes, understand structural typing, and model dictionaries with index signatures and Record.

Values that can be one of several types, exact-value types, and how TypeScript follows your if-statements to know which one you hold. Tagged unions, exhaustive checks and custom guards.

Read-only arrays, tuples, enums and their alternatives, object vs {} vs unknown, the never type, and type assertions with satisfies.

Typed classes, private and protected members, inheritance and override, abstract classes, implements, static members, accessors, this types and decorators.

Write one function, class or type that works for many types and keeps the exact type: type parameters, constraints, defaults, inference control and variance.

Build new types from old ones: keyof, typeof, indexed access, mapped types and key remapping, with the real type each operator produces.

Types that make decisions: conditional types, distribution over unions, infer, template literal types and recursive types, built one small step at a time.

The built-in utility types and how each is built, your own utilities, branded types, illegal states that cannot be written, and knowing when types get too clever.

Split code into files with import and export, learn how the compiler finds files, read and write .d.ts files, type third-party code and check plain JavaScript.

How tsc reads tsconfig.json, what strict and its extra flags catch, how target, lib and emit work, project references, ways to run TypeScript, and compiler speed.

Type the page you work with: DOM elements and events, promises and async code, data from fetch, errors, and browser storage, all checked by the compiler.

Type props, children, state, refs, reducers, events, forms, context, custom hooks, generic and polymorphic components, and the patterns that make React code safe.

Vite, Next.js and Node, linting with typescript-eslint, tests and type tests, migrating a JavaScript codebase, sharing types with a back end, and monorepos.

How the checker really decides, inference in depth, declaration merging, type-level programming, the deliberate soundness holes, and designing types for a library.

Interview answers backed by the compiler, live type challenges, a code-review checklist, and a fully typed task tracker built step by step.