JavaScript with types — safer, clearer code from basic types to generics.
A beginner-friendly guide to TypeScript: what it is, why it exists, how it adds optional static types on top of JavaScript, and how those types catch bugs before your code ever runs.
A beginner-friendly look at what TypeScript actually buys you: fewer runtime bugs, self-documenting code, smarter autocomplete, and safer refactors — plus an honest take on its costs.
TypeScript is JavaScript with static types and a compile step. Learn what they share, what TS adds, why .ts turns into .js, and which one to reach for as a beginner.
A beginner-friendly guide to setting up TypeScript: installing the tsc compiler, understanding tsconfig.json, compiling .ts to .js, watch mode, and where TypeScript fits in a modern toolchain.
A beginner-friendly tour of TypeScript's basic types — string, number, boolean, null, undefined, plus any, unknown, void, and never — with lots of small, practical examples.
Learn how to use the : Type syntax to annotate variables, function parameters, and return values in TypeScript, and when you actually need annotations versus letting TS figure types out for you.
Learn how TypeScript interfaces describe the shape of an object, plus optional and readonly properties and how to extend one interface from another, with clear beginner examples.
Learn how the type keyword lets you name strings, object shapes, and unions in TypeScript, how type aliases compare to interfaces, and when to reach for each one.
Learn how TypeScript union types let a value be one of several types, and how intersection types merge object shapes together — with clear, beginner-friendly examples.
Learn how to type arrays and tuples in TypeScript. Understand string[] vs Array<number>, when a fixed-length tuple is the right tool, and how readonly keeps your data safe.
Learn how enums in TypeScript group related constants under readable names. We cover numeric vs string enums, when they help, and the union-of-literals alternative.
Learn how TypeScript literal types let a value be one exact thing, like "small" or 404, and how literal unions model a finite set of allowed options with full safety.
A beginner-friendly guide to how TypeScript figures out types on its own, why you do not need to annotate everything, and when an explicit type is still the safer choice.
Learn how to type objects in TypeScript — inline shapes, type aliases and interfaces, nested objects, optional and readonly properties, and index signatures for dynamic keys.
A beginner-friendly guide to generics in TypeScript. Learn how type parameters let one function or container work with many types while keeping full type safety.
Learn how to type functions in TypeScript: parameter types, return types, optional, default, and rest parameters, function-type expressions, void, and a peek at overloads.
Learn how TypeScript upgrades JavaScript classes with typed fields, access modifiers, readonly, parameter properties, interfaces, and abstract classes — explained plainly for beginners.
Learn how TypeScript narrows a broad type, like a union, down to a specific type inside a block so you can use it safely. Covers typeof, instanceof, truthiness, equality, in, discriminated unions, and type guards.
A beginner-friendly tour of TypeScript's built-in utility types — Partial, Required, Readonly, Pick, Omit, Record, Exclude, and ReturnType — with small examples and a handy reference table.
Learn how to split TypeScript code across files with ES modules: import/export, named vs default exports, exporting types, import type, and how module resolution works.
Learn what TypeScript declaration files (.d.ts) are, how ambient declarations and the declare keyword work, and why you consume @types packages far more often than you write them.
A beginner-friendly introduction to decorators in TypeScript: what the @something syntax means, where you meet it, a simple example, and why it keeps evolving.
![Mapped Types cover with the syntax [K in keyof T]](/_astro/cover.hTMMfcpg_Z15vOeo.svg)
Learn how mapped types in TypeScript build a new type by transforming each property of an existing one, and how Partial and Readonly are made this way.
Learn how TypeScript types the browser DOM: element types like HTMLInputElement, why getElementById can return null, when type assertions are safe, and how to type event handlers cleanly.