A superset of JavaScript with static typing that compiles to JS

A separate language with its own runtime that browsers execute directly

A library for checking types while JavaScript code runs

TypeScript · Junior · Question 1 of 75

What is TypeScript?

✓Correct answer: A superset of JavaScript with static typing that compiles to JS
2A separate language with its own runtime that browsers execute directly
3A library for checking types while JavaScript code runs

Explanation

Any valid JS is almost always valid TS. Types are checked at compile time and then erased: plain JavaScript runs at runtime, and there are no type checks there. That's why external data (APIs, forms) is still validated at runtime - e.g. with Zod.

What is TypeScript?

Explanation

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