TypeScript vs JavaScript: What’s the difference between them?

TypeScript improves the shortcomings of JavaScript; adding syntactic sugar and static typing to the language. The additional features in TypeScript make it more powerful and safer for large software teams to collaborate and avoid bugs. It does add some complexity to a project, but one can argue that TypeScript is better than JavaScript.

No. In order to work with TypeScript, you will have to first learn JavaScript and then the additional features that TypeScript has. That said, if you already know JavaScript, picking up TypeScript should not be difficult. Plus, the additional benefits TypeScript offers (particularly for larger, complex projects) are likely worth the extra effort it takes to learn.

In the narrow sense, yes, you could write all of your project code in TypeScript, effectively replacing JavaScript with TypeScript. However, in the broader sense, no, TypeScript will not completely replace JavaScript because it depends on JavaScript and is ultimately compiled into JavaScript in order to run in the browser (or on the server).