Classes in TypeScript

Last reviewed May 28, 2026 Content v20260528

Track mode

client_typescript

Means

In-browser TS

Reading

~1 min

Level

intermediate

This lesson

This lesson teaches Classes in TypeScript—the ideas, syntax, and habits you need before moving on in TypeScript.

Without a solid grasp of Classes in TypeScript, you will repeat mistakes in TypeScript exercises and on real pages or scripts.

You will apply Classes in TypeScript in contexts like: Modern front-end apps, Node APIs, and any team that standardizes on TS-first tooling.

Write TypeScript, compile in the browser, run the emitted JavaScript, and check understanding with MCQs.

Toward the end of the track—use it to consolidate patterns before the capstone or summary lessons.

Classes support access modifiers (public, private, protected), readonly fields, and implemented interfaces.

vs structural types

Classes create nominal-ish behavior at runtime (prototype chain) while TypeScript still compares instance shapes structurally when assigning to interfaces.

Self-check

Implement a small class that satisfies an interface with read(): number.

Parameter properties in constructors (constructor(private id: string)) reduce boilerplate in service classes.

Practice: Apply classes-in-ts in the playground, then explain classes in ts in one sentence without looking at notes.

Playground

Runs in your browser in a sandboxed frame. Backend runners appear when this track’s profile allows them.

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