Quiz · First steps · lesson 2 of 7Quiz — TypeScript and JavaScriptWhat is TypeScript and how does it differ from JavaScript?[A]JavaScript whose types are checked while the program runs: the annotations stay in the code, and a value of the wrong type throws a TypeError at the moment it is put into a variable with a type.[B]JavaScript with type annotations: the compiler tsc checks the types before the program runs, then writes plain JavaScript with the types removed. Any JavaScript code is TypeScript code too.[C]A separate language with its own engine: browsers run TypeScript files as they are and check the types themselves, while the compiler tsc only shrinks the code before it is published.[D]A strict subset of JavaScript: it bans the loosest parts of the language, such as var and the == comparison, so the compiler tsc will not even parse a .ts file that uses them.← BackWhy TypeScriptNext →Running TypeScript
